Functional Polymeric Nanoparticles: An Efficient and Promising Tool for Active Delivery of Bioactives

Abstract

Nanotechnology is a multidisciplinary field and has achieved breakthroughs in bioengineering, molecular biology, diagnostics, and therapeutics. A recent advance in nanotechnology is the development of a functional nanosystem by incorporation, adsorption, or covalent coupling of polymers, carbohydrates, endogenous substances/ligands, peptides, proteins, nucleic acids, and polysaccharides to the surface of nanoparticles. Functionalization confers a wide array of interesting properties such as stealth characteristics, a bioadhesive property, and that it prevents aggregation of nanoparticles, imparts biostability and solubility, reduces toxicity, and provides site-specific delivery. This makes the nanosystem an intelligent tool for diagnostics, prognostics, and controlled and sustained delivery of protein, peptide, pDNA, and other therapeutic agents to specific targets (tissue, cell, and intracellular). Various types of functional nanosystems, such as carbon nanotubes, quantum dots, polymeric micelles, dendrimers, metallic nanoparticles, and liposomes, are being extensively explored. However, high tissue accumulation of nonbiodegradable nanoparticles has caused toxicity problems and rendered them as not-so-popular therapeutic and diagnostic systems. The toxicity and safety of nonbiodegradable nanoparticles are subject to future research. Polymeric nanoparticles have offered attractive alternative modules due to biocompatibility, nonimmunogenicity, nontoxicity, biodegradability, simple preparation methods, high physical stability, possibility of sustained drug release, and higher probability for surface functionalization. Depending on properties that have been modified, polymeric nanoparticles can be grouped in to four classes, namely, stealth, polysaccharide decorated biomimetic, bioadhesive, and ligand-anchored functional polymeric nanoparticles (f-PNPs). This review explores the ligand-anchored f-PNP as a carrier for active delivery of bioactives, envisaged to date. This review also details the ligands available for conjugation, their method of coupling to nanoparticles, and applications of f-PNPs in anticancer drug delivery, oral delivery, gene delivery, vaccine delivery, and intracellular delivery; site-specific delivery to liver, macrophages, lymphatics, and brain; and miscellaneous applications. This review also addresses formidable challenges encountered, and proposes some future strategies for development of a promising site-specific active delivery system.

Smart Hydrogel Particles: Biomarker Harvesting: One-Step Affinity Purification, Size Exclusion, and Protection against Degradation

“…Measured values were then converted to particle sizes via the Stokes-Einstein relationship 36 . NIPAm particle size decreased with increasing temperature (Figure 2A), which is a distinctive characteristic of thermo responsive hydrogels [28][29][30][31][32][33] . The NIPAm/AAc particles showed a similar temperature dependence with respect to particle size, however they also demonstrated a pH dependent behavior ( Figure 2B).…”

Biomaterials for the central nervous system

“…Compared with liposomes, polymeric NPs are more stable when in contact with the biological fluids. Also, their polymeric nature permits the attainment of desired properties such as controlled and sustained drug release, allowing drug release at the targeted site over a period of days or even weeks after injection (Garcia-Garcia et al 2005;Roney et al 2005;Nahar et al 2006). Drug release from NPs is mediated by drug desorption, diffusion through the NP matrix, polymer wall degradation of NPs or some combination of these mechanisms (Lockman et al 2002;Misra et al 2003).…”

Gene Therapy for Parkinson’s Disease: Towards Non Invasive Approaches

“…These advantages stem from two basic properties: 1) their small size favors penetration through small capillaries, allowing a greater accumulation of the drug /gene at the target site (Soppimath et al, 2001), this is particularly relevant in the CNS, in which the transport of some drugs is limited because of their inability to cross the BBB and 2) the application of nanoparticles as vehicles for transport of drugs / genes may help overcome this obstacle. In fact, it has recently been shown that polymeric nanoparticles are effective for the transport of peptides and other agents through the BBB (Kreuter et al, 2003;Nahar et al, 2006). The use of biodegradable polymers favors the sustained release of drugs / genes into the target site over a long period (Tang et al, 2009).…”