Self-assembly of amphiphilic block copolymers display a multiplicity of nanoscale periodic patterns proposed as a dominant tool for the ‘bottom-up’ fabrication of nanomaterials with different levels of ordering. The present review article focuses on the recent updates to the self-association of amphiphilic block copolymers in aqueous media into varied core-shell morphologies. We briefly describe the block copolymers, their types, microdomain formation in bulk and micellization in selective solvents. We also discuss the characteristic features of block copolymers nanoaggregates viz., polymer micelles (PMs) and polymersomes. Amphiphilic block copolymers (with a variety of hydrophobic blocks and hydrophilic blocks; often polyethylene oxide) self-assemble in water to micelles/niosomes similar to conventional nonionic surfactants with high drug loading capacity. Double hydrophilic block copolymers (DHBCs) made of neutral block-neutral block or neutral block-charged block can transform one block to become hydrophobic under the influence of a stimulus (physical/chemical/biological), and thus induced amphiphilicity and display self-assembly are discussed. Different kinds of polymer micelles (viz. shell and core-cross-linked, core-shell-corona, schizophrenic, crew cut, Janus) are presented in detail. Updates on polymerization-induced self-assembly (PISA) and crystallization-driven self-assembly (CDSA) are also provided. Polyion complexes (PICs) and polyion complex micelles (PICMs) are discussed. Applications of these block copolymeric micelles and polymersomes as nanocarriers in drug delivery systems are described.

Degradable polymers (both biomacromolecules and several synthetic polymers) for biomedical applications have been promising very much in the recent past due to their low cost, biocompatibility, flexibility, and minimal side effects. Here, we present an overview with updated information on natural and synthetic degradable polymers where a brief account on different polysaccharides, proteins, and synthetic polymers viz. polyesters/polyamino acids/polyanhydrides/polyphosphazenes/polyurethanes relevant to biomedical applications has been provided. The various approaches for the transformation of these polymers by physical/chemical means viz. cross-linking, as polyblends, nanocomposites/hybrid composites, interpenetrating complexes, interpolymer/polyion complexes, functionalization, polymer conjugates, and block and graft copolymers, are described. The degradation mechanism, drug loading profiles, and toxicological aspects of polymeric nanoparticles formed are also defined. Biomedical applications of these degradable polymer-based biomaterials in and as wound dressing/healing, biosensors, drug delivery systems, tissue engineering, and regenerative medicine, etc., are highlighted. In addition, the use of such nano systems to solve current drug delivery problems is briefly reviewed.

Soft tissue reconstructs require materials that form three-dimensional (3-D) structures supportive to cell proliferation and regenerative processes. Polysaccharides, due to their hydrophilicity, biocompatibility, biodegradability, abundance, and presence of derivatizable functional groups, are distinctive scaffold materials. Superior mechanical properties, physiological signaling, and tunable tissue response have been achieved through chemical modification of polysaccharides. Moreover, an appropriate formulation strategy enables spatial placement of the scaffold to a targeted site. With the advent of newer technologies, these preparations can be tailor-made for responding to alterations in temperature, pH, or other physiological stimuli. In this review, we discuss the developmental and biological aspects of scaffolds prepared from four polysaccharides, viz. alginic acid (ALG), chitosan (CHI), hyaluronic acid (HA), and dextran (DEX). Clinical studies on these scaffolds are also discussed.

Pluronics® are considered to be good carriers for poorly water soluble substances on account of their superior solubilization capacity over other ionic and nonionic surfactants. Understanding the influence of these substances on the aggregation characteristics of Pluronics® is therefore of overriding importance. In this manuscript we report dynamic light scattering, small angle neutron scattering, fluorescence and viscometry studies on the effect of adding hydrophobic alcohols viz. hexan-1-ol, octan-1-ol and decan-1-ol to the aqueous solutions of two Pluronics® (P85 and P123) with different hydrophilic–lipophilic balances. Both these Pluronics® exhibit a sphere to rod micellar shape transition with increasing temperature, the dynamics of the transition being significantly slower in the case of P123 because of its higher hydrophobicity and molecular weight. The aim of our studies was to investigate the restructuring and growth of Pluronic® micelles upon addition of hydrophobic alcohols that have applications in fields ranging from personal care/food products to pharmaceutical formulations. The studies show that alcohol induced micellar restructuring and growth for the two Pluronics® slow down as the concentration of alcohol increases and in addition their aqueous solubility decreases progressively from hexan-1-ol to decan-1-ol. These observations, which were manifested by a decreasing rate of sphere to rod micellar growth, have been attributed to more effective dehydration of the micellar core by alcohols with higher levels of solubilization and hydrophobicity. The results thus shed light on the specific role of additive induced dehydration of micellar cores in the restructuring and growth characteristics of micelles, for both hydrophilic (P85) and hydrophobic (P123) Pluronics®.