Nanoparticles: Classification, Synthesis, Characterization, and Applications

Objective: This review aims to present a comprehensive overview of nanoparticles, focusing on their classification, physicochemical properties, synthesis methods, characterization techniques, and diverse scientific applications.
Methods: Relevant studies and review articles were collected from major databases such as PubMed, ScienceDirect, SpringerLink, and Scopus. Various chemical, physical, and biological synthesis approaches were analyzed, along with modern characterization techniques such as electron microscopy, spectroscopy, and thermal analysis.
Results: Findings indicate that nanoparticles possess distinctive properties, including high surface-to-volume ratio and tunable morphology, which enhance their efficiency in drug delivery, imaging catalysis, and energy storage. Biologically synthesized nanopartilces demonstrated better biocompatibility and reduced toxicity compared to chemically prepared ones
Conclusion: Nanoparticles represent a rapidly advancing field with vast biomedical and industrial applications. However, biosafety, toxicity, and environmental concerns require further systematic investigation to ensure their safe and sustainable use.

Nanoparticles, Synthesis, Characterization, Drug Delivery, Biomedical Applications, Toxicity

1. Ealias, A. M., & Saravanakumar, M. P. (2017). A review on the classification, characterisation, synthesis of nanoparticles and their application. IOP Conference Series: Materials Science and Engineering, 263(3). https://doi.org/10.1088/1757 899X/263/3/032019 [Google Scholar] [Crossref]

2. Khan, I., Saeed, K., & Khan, I. (2019). Nanoparticles: Properties, applications and toxicities. In Arabian Journal of Chemistry (Vol. 12, Issue 7, pp. 908–931). Elsevier B.V. https:// doi.org/10.1016/j.arabjc.2017.05.011 [Google Scholar] [Crossref]

3. Hasan, S. (2015). A Review on Nanoparticles: Their Synthesis and Types. In Research Journal of Recent Sciences (Vol. 4). www.isca.me [Google Scholar] [Crossref]

4. Konwar, R., & Ahmed, A. B. (2016). nanoparticle: an overview of preparation, characterization and application. International Research Journal of Pharmacy, 4(4), 47–57. https://doi.org/10.7897/2230-8407.04408 [Google Scholar] [Crossref]

5. .Kumari, S., & Sarkar, L. (2021). A Review on Nanoparticles: Structure, Classification, Synthesis & Applications. journal of scientific research, 65(08), 42–46. https://doi.org/10.37398/jsr.2021.650809 [Google Scholar] [Crossref]

6. Altammar, K. A. (2023). A review on nanoparticles: characteristics, synthesis, applications, and challenges. In Frontiers in Microbiology (Vol. 14). Frontiers Media S.A. https:// doi.org/ 10. 3389/ fmicb.2023.1155622 [Google Scholar] [Crossref]

7. Gavrilescu1, C.-M., Paraschiv1, C., Horjinec1, P., Sotropa1, D.-M., & Barbu1, R. M. (n.d.). the advantages and disadvantages of nanotechnology. In Romanian Journal of Oral Rehabilitation (Vol. 10, Issue 2). [Google Scholar] [Crossref]

8. Ghule, N. W., Haque Bamer, A., & Kalaskar, M. G. (n.d.). Metal nanoparticles synthesis: An overview on methods of preparation, advantages and disadvantages, and applications Author links open overlay panelPrasad Govindrao Jamkhande. https://doi.org/10.1016/j.jddst.2019.101174G et [Google Scholar] [Crossref]

9. Radkhah ali reza, E. S. S. H. M. (2021). Review on the benefit and disadvantage of nanotechnology in the aquaculture. Journal of Ornamental Aquatics, 8(2), 43–58. [Google Scholar] [Crossref]

10. Singh, J., Dutta, T., Kim, K. H., Rawat, M., Samddar, P., & Kumar, P. (2018). “Green” synthesis of metals and their oxide nanoparticles: Applications for environmental remediation. In Journal of Nanobiotechnology (Vol. 16, Issue 1). BioMed Central Ltd. https://doi.org/10.1186/s12951-018-0408-4 [Google Scholar] [Crossref]

11. Chellaram, C., Murugaboopathi, G., John, A. A., Sivakumar, R., Ganesan, S., Krithika, S., & Priya, G. (2014). Significance of Nanotechnology in Food Industry. APCBEE Procedia, 8, 109–113. https:// doi.org/10.1016/j.apcbee.2014.03.010 [Google Scholar] [Crossref]

12. Sharma, A., & Nanochemistry :(2023) Oza, G. (n.d.). synthesis, characterization and applications.(Edition.1, pp.11) ISBN – 9781003081944. [Google Scholar] [Crossref]

13. Tripathy, S. (2023). Top-down and Bottom-up Approaches for Synthesis of Nanoparticles (pp. 92–130). https://doi.org/10.21741/9781644902370-4 [Google Scholar] [Crossref]

14. Ghazal, H., Khaleed, N., & Abdelaziz, E. (2023). Significance Advantages, and Disadvantages of Nanotechnology in Textile Finishing. Egyptian Journal of Chemistry, 0(0), 0–0. https://doi.org/10.21608/ejchem.2023.19512 1.7624 [Google Scholar] [Crossref]

15. Prasad Yadav, T., Manohar Yadav, R., & Pratap Singh, D. (2012). Mechanical Milling: a Top Down Approach for the Synthesis of Nanomaterials and Nanocomposites. Nanoscience and Nanotechnology, 2(3), 22 48. https://doi.org/10.5923/j.nn.20120203.01 [Google Scholar] [Crossref]

16. Rajput, N. (2015). methods of preparation of nanoparticles-a review. In International Journal of Advances in Engineering & Technology (Vol. 7). [Google Scholar] [Crossref]

17. Okuyama K, L. W. I. (2003). Preparation of nanoparticles via spray route. Chemical Engineering Science, 58(3–6), 537–547. https://doi.org/10.1016/S0009 2509(02)00578-XGet [Google Scholar] [Crossref]

18. Devi P, S. S. K. N. et. al,. (2023). Nanotechnology and their various methods for synthesis of nanoparticles. Enviromental, Indutrialization, Management, Economics, Agriculture, Rural and Urban Development towards Sustainable Potential, [Google Scholar] [Crossref]

19. Ijaz I, Gilani. E. al,. (2020). Full article_ Detail review on chemical, physical and green synthesis, classification, characterizations and applications of nanoparticles. Green Chemistry Letters and Reviews, 13(3), 223 245. https://doi.org/https://doi.org/10.1080/17518 253.2020.1802517 [Google Scholar] [Crossref]

20. Fu, X., Cai, J., Zhang, X., Li, W. di, Ge, H., & Hu, Y. (2018). Top-down fabrication of shape-controlled, monodisperse nanoparticles for biomedical applications. In Advanced Drug Delivery Reviews (Vol. 132, pp. 169 187). Elsevier B.V. https://doi.org/10.1016/j.addr.2018.07.006 [Google Scholar] [Crossref]

21. Barhoum, A., García-Betancourt, M. L., Jeevanandam, J., Hussien, E. A., Mekkawy, S. A., Mostafa, M., Omran, M. M., Abdalla, M. S., & Bechelany, M. (2022). Review on Natural, Incidental, Engineered Bioinspired, Nanomaterials: and History, Definitions, Classifications, Synthesis, Properties, Market, Toxicities, Risks, and Regulations. Nanomaterials, 12(2). https:// doi.org/ 10.3390/ nano 12020177 [Google Scholar] [Crossref]

22. Varma, M. M., Kumar, K. T. S., & Durga Srivalli, I. (2021). nanoparticles: a characterization review on synthesis, and applications. In Certified Journal │ Srivalli et al. World Journal of Pharmaceutical and Medical Research (Vol. 7). www.wjpmr.com [Google Scholar] [Crossref]

23. Harishchandra, B. D., Pappuswamy, M., PU, A., Shama, G., A, P., Arumugam, V. A., Periyaswamy, T., & Sundaram, R. (2020). Copper Nanoparticles: A Review on Synthesis, Characterization and Applications. Asian Pacific Journal of Cancer Biology, 5(4), 201–210. https:// doi.org/ 10.31557/ apjcb .2020.5.4.201 210 [Google Scholar] [Crossref]

24. Kumari, S., & Sarkar, L. (2021). A Review on Nanoparticles: Structure, Classification, Synthesis & Applications. JOURNAL OF SCIENTIFIC RESEARCH, 65(08), 42–46. https://doi.org/ 10.37398/ jsr.2021.650809 [Google Scholar] [Crossref]

25. FSAI (2008). The Relevance for food safety of applications of nanotechnology in the food and feed industries. Edited by Food Safety Authority of Ireland Abbey Court, Dublin p. 82 [Google Scholar] [Crossref]

26. Pandey, P., & Dahiya, M. (2016). a brief review on inorganic nanoparticles. Journal of critical reviews.(Vol.3,issue 3).ISSN-2394-5125. [Google Scholar] [Crossref]

27. Murray CB, Kagan CR, Bawendi MG: Synthesis and characterization of monodisperse nanocrystals and close-packed nanocrystal assemblies. Annu Rev Mater Sci 2000, 30:545-610. [Google Scholar] [Crossref]

28. R. Pandey and G. K. Khuller, “Nanotechnology Based Drug Delivery System(s) for the Management of Tuber-culosis,” Indian Journal of Experimental Biology, Vol. 44, No. 5, 2006, pp. 357-366. [Google Scholar] [Crossref]

29. R. Das, S. S. Nath, D. Chakdar, G. Gope and R. Bhat-tacharjee, “Preparation of Silver Nanoparticles and Their Characterization,” AZojono Journal of Nanotechnology Online, Vol. 5, No. 10, 2009, p. 2240. [Google Scholar] [Crossref]

30. Mu L, Feng SS. Fabrication, characterization and in vitro release of paclitaxel (Taxol) loaded poly (lactic-co-glycolic acid) microspheres prepared by spray drying technique with lipid/cholesterol emulsifiers. J Control Release 2001; 76(3):239-254. [Google Scholar] [Crossref]

31. Avnika Tomar and Garima Garg, Short Review on Application of Gold Nanoparticles. Global Journal of Pharmacology, 7 (1), 34-38, (2013) [Google Scholar] [Crossref]

32. Luo, X.; Morrin, A.; Killard, A. J.; Smyth, M. R. (2006). "Application of Nanoparticles in Electrochemical Sensors and Biosensors". Electroanalysis.18: 319– 326. [Google Scholar] [Crossref]

33. Ramyadevi, J.; Jeyasubramanian, K.; Marikani, A.; Rajakumar, G.; Rahuman, A. A. (2012). "Synthesis and antimicrobial activity of copper nanoparticles". [Google Scholar] [Crossref]

34. Sozer N, Kokini JL (2009). Nanotechnology and its applications in the food sector. Trends Biotechnol. 27:82-89. [Google Scholar] [Crossref]

35. Sanguansri P, Augustin MA (2006). Nanoscale materials development – a food industry perspective. Trends Food Sci. Technol. 17:547-556 [Google Scholar] [Crossref]

36. Neeraj kumar, Anubhav Dubey, Ashish Mishra, Pallavi Tiwari. Formulation and Evaluation of Metoprolol Succinate Loaded Ethosomal Gel for Transdermal Delivery. JCR. 2020; 7(6): 1772-1782 [Google Scholar] [Crossref]

37. Raj Pratap Singh , Dr. Vishal Dubey ,Anubhav Dubey & Dr. Shantanu, Liposomal gels for vaginal drug delivery of Amoxicillin Trihydrate, International Journal of Medical Research and Pharmaceutical Sciences;2020 7(8) 1-13. [Google Scholar] [Crossref]

38. Shruti Khare , Dr.Swatantra Kushwaha , Amit Mishra & Prerna Bajpayi, method development for simultaneous estimation of atorvastatin and nateglinide in combined dosage form by uv spectroscopy, Indian Journal of Medical Research and Pharmaceutical Sciences September 2020;7(9)16 21. [Google Scholar] [Crossref]

39. Alavi, M., & Nokhodchi, A. (2022). Micro- and nanoformulations of paclitaxel based on micelles, liposomes, cubosomes, and lipid nanoparticles: Recent advances and challenges. In Drug Discovery Today (Vol. 27, Issue 2, pp. 576–584). Elsevier Ltd. https://doi.org/10.1016/j.drudis.2021.10.007 [Google Scholar] [Crossref]

40. Al-Maliki, R. M., Alsalhy, Q. F., Al-Jubouri, S., Salih, I. K., AbdulRazak, A. A., Shehab, M. A., Németh, Z., & Hernadi, K. (2022). Classification of Nanomaterials and the Effect of Graphene Oxide (GO) and Recently Developed Nanoparticles Ultrafiltration on the Membrane and Their Applications: A Review. In Membranes (Vol. 12, Issue 11). MDPI. https://doi.org/10.3390/membranes12111043 [Google Scholar] [Crossref]

41. De Leo, V., Maurelli, A. M., Giotta, L., & Catucci, L. (2022). Liposomes containing nanoparticles: preparation and applications. In Colloids and Surfaces B: Biointerfaces (Vol. 218). Elsevier B.V. https://doi.org/10.1016/j.colsurfb.2022.11273 7 [Google Scholar] [Crossref]

42. Salata O. (2004). Apllication of nanoparticles in biology and medicine. Journal of Nanobiotechnology. [Google Scholar] [Crossref]

43. Dash, K. K., Deka, P., Bangar, S. P., Chaudhary, V., Trif, M., & Rusu, A. (2022). Applications of Inorganic Nanoparticles in Food Packaging: A Comprehensive Review. In Polymers (Vol. 14, Issue 3). MDPI. https://doi.org/10.3390/polym14030521 [Google Scholar] [Crossref]

44. Amina, S. J., & Guo, B. (2020). A review on the synthesis and functionalization of gold nanoparticles as a drug delivery vehicle. In International Journal of Nanomedicine (Vol. 15, pp. 9823–9857). Dove Medical Press Ltd. https://doi.org/10.2147/IJN.S279094 [Google Scholar] [Crossref]

45. Khan, Y., Sadia, H., Ali Shah, S. Z., Khan, M. N., Shah, A. A., Ullah, N., Ullah, M. F., Bibi, H., Bafakeeh, O. T., Khedher, N. ben, Eldin, S. M., Fadhl, B. M., & Khan, M. I. (2022). Classification, Synthetic, Characterization Approaches and to Nanoparticles, and Their Applications in Various Fields of Nanotechnology: A Review. In Catalysts (Vol. 12, Issue 11). MDPI. https://doi.org/ 10.3390/ catal12111386 [Google Scholar] [Crossref]

46. Dizaj, S. M., Lotfipour, F., Barzegar-Jalali, M., Zarrintan, M. H., & Adibkia, K. (2014). Antimicrobial activity of the metals and metal oxide nanoparticles. In Materials Science and Engineering C (Vol.44,pp. 78–284). Elsevier Ltd. https://doi.org/10.1016/j.msec.2014.08.031 [Google Scholar] [Crossref]

47. Zahoor, M., Nazir, N., Iftikhar, M., Naz, S., Zekker, I., Burlakovs, J., Uddin, F., Kamran, A. W., Kallistova, A., Pimenov, N., & Khan, F. A. (2021). A review on silver nanoparticles: Classification, various methods of synthesis, and their potential roles in biomedical applications and water treatment. In Water (Switzerland) (Vol. 13, Issue 16). MDPI. https://doi.org/10.3390/w13162216 [Google Scholar] [Crossref]

48. Calderón-Jiménez, B., Johnson, M. E., Montoro Bustos, A. R., Murphy, K. E., Winchester, M. R., & Baudrit, J. R. V. (2017). Silver nanoparticles: Technological advances, societal impacts, and metrological challenges. In Frontiers in Chemistry (Vol. 5, Issue Feb). Frontiers Media S. A. https://doi.org/10.3389/fchem.2017.00006 [Google Scholar] [Crossref]

49. Milosavljevic.V, Mitrevska. K, & Adam. V, (2022). Benefits of oxidation and size reduction of graphene/graphene oxide nanoparticles in biosensing application: Classification of graphene/graphene oxide nanoparticles. In Sensors and Actuators B: Chemical (Vol. 353). Elsevier B.V. https://doi.org/10.1016/j.snb.2021.131122 [Google Scholar] [Crossref]

50. Prakash, A., R, P. R., P A, D., & P B, A. (2020). A Review on Nanoparticles. International Journal of Pharmaceutical Sciences Review and Research, 64(1), 64–68. https://doi.org/ 10.47583/ ijpsrr.2020 .v64i01.0 12 [Google Scholar] [Crossref]

51. Nikam, A. P., Ratnaparkhiand, M. P., & Chaudhari, S. P. (n.d.). nanoparticles an overview. 3(5), 1121–1127. www.ijrdpl.com [Google Scholar] [Crossref]

52. Nour M, H. O. et. al,. (2022). Utilization of gold nanoparticles for the detection of squamous cell carcinoma of the tongue based on laser-induced fluorescence and diffuse reflectance characteristics: an in vitro study Similar content being viewed by others.(Vol.37, pp.3551-3560). [Google Scholar] [Crossref]

53. Elmowafy, M. Skin penetration/permeation success determinants of nanocarriers: Pursuit of a perfect formulation. Colloids Surf. B Biointerfaces 2021, 203, 111748. [CrossRef] [PubMed] [Google Scholar] [Crossref]

54. Chen,Y.; Feng, X. Gold nanoparticles for skin drug delivery. Int. J. Pharm. 2022, 625, 122122. [CrossRef] [PubMed] [Google Scholar] [Crossref]

55. Phatale, V.; Vaiphei, K.K.; Jha, S.; Patil, D.; Agrawal, M.; Alexander, A. Overcoming skin barriers through advanced transdermal drug delivery approaches. J. Control. Release 2022, 351, 361–380. [CrossRef] [Google Scholar] [Crossref]

56. Yang, D.; Chen, M.; Sun, Y.; Jin, Y.; Lu, C.; Pan, X.; Quan, G.; Wu, C. Microneedle-mediated transdermal drug delivery for treating diverse skin diseases. Acta Biomater. 2021, 121, 119–133. [CrossRef] [Google Scholar] [Crossref]

57. Sabbagh, F.; Kim, B.S. Recent advances in polymeric transdermal drug delivery systems. J. Control. Release 2022, 341, 132–146. [CrossRef] [Google Scholar] [Crossref]

58. Shen, S.; Zheng, X.; Dong, X.; Fang, M.; Wan, A.; Zhu, T.; Yang, Q.; Xie, J.; Yan, Q. Methotrexate-loaded hyaluronan-modified liposomes integrated into dissolving microneedles for the treatment of psoriasis. Eur. J. Pharm. Sci. 2024, 195, 106711. [CrossRef] [PubMed] [Google Scholar] [Crossref]

59. Shah, P.; Goodyear, B.; Haq, A.; Puri, V.; Michniak-Kohn, B. Evaluations of Quality by Design (QbD) Elements Impact for Developing Niosomes as a Promising Topical Drug Delivery Platform. Pharmaceutics 2020, 12, 246. [CrossRef] [PubMed] [Google Scholar] [Crossref]

60. He, E.; Li, H.; Li, X.; Wu, X.; Lei, K.; Diao, Y. Transdermal Delivery of Indirubin-Loaded Microemulsion Gel: Preparation, Characterization and Anti-Psoriatic Activity. Int. J. Mol. Sci. 2022, 23, 3798. [CrossRef] [Google Scholar] [Crossref]

61. Chamcheu, J.C.; Siddiqui, I.A.; Adhami, V.M.; Esnault, S.; Bharali, D.J.; Babatunde, A.S.; Adame, S.; Massey, R.J.; Wood, G.S.; Longley, B.J.; et al. Chitosan-based nanoformulated (–)-epigallocatechin-3-gallate (EGCG) modulates human keratinocyte-induced responses and alleviates imiquimod-induced murine psoriasiform dermatitis. Int. J. Nanomed. 2018, 13, 4189–4206. [CrossRef] [Google Scholar] [Crossref]

62. Zhang, X.; Wu, Y.; Gong, H.; Xiong, Y.; Chen, Y.; Li, L.; Zhi, B.; Lv, S.; Peng, T.; Zhang, H. A Multifunctional Herb-Derived Glycopeptide Hydrogel for Chronic Wound Healing. Small 2024, 20, e2400516. [CrossRef] [PubMed] [Google Scholar] [Crossref]

63. Yang, J.; He, Y.; Nan, S.; Li, J.; Pi, A.; Yan, L.; Xu, J.; Hao, Y. Therapeutic effect of propolis nanoparticles on wound healing. J. Drug Deliv. Sci. Technol. 2023, 82, 104284. [CrossRef] [Google Scholar] [Crossref]

64. Kazemi, M.; Mombeiny, R.; Tavakol, S.; Keyhanvar, P.; Mousavizadeh, K. A combination therapy of nanoethosomal piroxicam formulation along with iontophoresis as an anti-inflammatory transdermal delivery system for wound healing. Int. Wound J. 2019, 16, 1144–1152. [CrossRef] [PubMed] [Google Scholar] [Crossref]

65. Guo, H.; Ran, W.; Jin, X.; Huang, Y.; Long, F.; Xiao, Y.; Gan, R.-Y.; Wu, Y.; Gao, H. Development of pectin/chitosan-based electrospun biomimetic nanofiber membranes loaded with dihydromyricetin inclusion complexes for wound healing application. Int. J. Biol. Macromol. 2024, 278, 134526. [CrossRef] [Google Scholar] [Crossref]

66. Liu, F.; Cheng, Z.; Yi, H. NIR light-activatable dissolving microneedle system for melanoma ablation enabled by a combination of ROS-responsive chemotherapy and phototherapy. J. Nanobiotechnol. 2023, 21, 61. [CrossRef] [PubMed] [Google Scholar] [Crossref]

67. Song, G.; Sun, Y.; Liu, T.; Zhang, X.; Zeng, Z.; Wang, R.; Li, P.; Li, C.; Jiang, G. Transdermal delivery of Cu-doped polydopamine using microneedles for photothermal and chemodynamic synergistic therapy against skin melanoma. Chem. Eng. J. 2021, 426, 130790. [CrossRef] [Google Scholar] [Crossref]

68. Silva, M.I.; Barbosa, A.I.; Costa Lima, S.A.; Costa, P.; Torres, T.; Reis, S. Freeze-Dried Softisan® 649-Based Lipid Nanoparticles for Enhanced Skin Delivery of Cyclosporine A. Nanomaterials 2020, 10, 986. [CrossRef] [Google Scholar] [Crossref]

69. Apps, Michael G.; Choi, Eugene H. Y.; Wheate, Nial J. (2015). "The state-of-play and future of platinum drugs". Endocrine-Related Cancer. 22 (4): R219 – R233. doi:10.1530/ERC-15-0237. hdl:2123/24426. PMID 26113607. [Google Scholar] [Crossref]

70. Stathopoulos, G. P.; Boulikas, T.; Vougiouka, M.; Deliconstantinos, G.; Rigatos, S.; Darli, E.; Viliotou, V.; Stathopoulos, J. G. (2005). "Pharmacokinetics and adverse reactions of a new liposomal cisplatin (Lipoplatin): Phase I study". Oncol. Rep. 13 (4): 589–595. PMID 15756428. [Google Scholar] [Crossref]

71. Boulika, Teni (2009). "Clinical overview on Lipoplatin: A successful liposomal formulation of cisplatin". Expert Opin. Investig. Drugs. 18 (8): 1197–1218. doi:10.1517/13543780903114168. [Google Scholar] [Crossref]

72. Boulikas, Teni; Stathopoulos, Georgios P.; Volakakis, Nikolaos; Vougiouka, Maria (2005). "Systemic lipoplatin infusion results in preferential tumor uptake in human studies" (PDF). Anticancer Res. 25 (4): 3031–3039. PMID 16080562. [Google Scholar] [Crossref]

73. Committee for Orphan Medicinal Products (30 November 2007). "Public Summary of Positive Opinion for Orphan Designation of Cisplatin (Liposomal) for the Treatment of Pancreatic Cancer" (PDF). European Medicines Agency. Archived from the original (PDF) on 26 April 2012. Retrieved 25 March 2010. [Google Scholar] [Crossref]

74. Casagrande, Naike; Celegato, Marta; Borghese, Cinzia; Mongiat, Maurizio; Colombatti, Alfonso; Aldinucci, Donatella (2014). "Preclinical activity of the liposomal cisplatin lipoplatin in ovarian cancer". Clinical Cancer Research. 20 (21): 5496–5506. doi:10.1158/1078-0432.CCR-14-07 13 . PMID 25231401. [Google Scholar] [Crossref]

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