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Plant antioxidants can be applied in the management of various human diseases. Despite these, extraction of these compounds still suffers from residual solvent impurities, low recovery yields, and the risks of undesirable chemical changes. Inspired by the protein–lipid interactions in the cell membranes, we proposed using poly(styrene-alt-maleic acid) (PSMA) to destabilize and associate with the bilayer lipids into the membrane-like nanodiscs. Such nanostructures could serve as protective reservoirs for the active compounds to reside with preserved bioactivities. This concept was demonstrated in the antioxidant extraction from robusta coffee leaves. Results indicated that aqueous PSMA extraction (no buffer agent) yielded products with the highest contents of phenolic acids (11.6 mg GAE·g−1) and flavonoids (9.6 mg CE·g−1). They also showed the highest antioxidant activity (IC50 = 3.7 µg·mL−1) compared to those obtained by typical sodium dodecyl sulfate and water extraction. This biomimetic approach could be considered for developing environmentally friendly extraction protocols in the future.

Ability of poly (styrene-alt-maleic anhydride) (PSMA) to undergo a conformational transition into an amphipathic α-helix coil offers one possible mechanism by which PSMA surface activity can be switched on or off in response to the pH change. This behaviour allows it to be useful in membrane solubilization for extraction technology. Bioactive compounds are recovered from plant tissues for different reasons. One of the most important reasons is due to the increased demand in nutraceuticals market and modern therapeutics. Despite this, aqueous-based extraction of these compounds has been reported to give low extraction yield. A development of new green extraction protocol is still a challenging task for all researchers nowadays. This study demonstrated, for the first time, possible use of PSMA as a lysis agent for plant bioactive compound extraction. To enhance its membrane affinity at physiological pH, the polymer was esterified with methanol. Both PSMA and its derivative (ePSMA) were characterized in terms of their membrane binding affinity through a combined use of both surface characterization and physical techniques. Analysis of the ternary phase diagrams suggested that ePSMA could facilitate stronger hydrophobically-driven interactions with the lipid. This was convinced by the reduced critical PSMA/lipid mass ratio from 7:1 (PSMA) to 1:1 (ePSMA), as observed in the ternary phase diagrams. Last but not the least, the crude extracts of Coffea robusta leaves obtained from ePSMA-based extraction showed a total phenolic content of 20.32±0.75 mg/g sample, significantly higher than that from the PSMA- (14.24±1.27 mg/g sample) and aqueous-based (16.33±1.03 mg/g sample) extractions. A structural manipulation of PSMA is thus a key to tailor its membrane solubilization and so, the extraction efficacy of bioactive compounds from plant cells.

Various lubricating body fluids at tissue interfaces are composed mainly of combinations of phospholipids and amphipathic apoproteins. The challenge in producing synthetic replacements for them is not replacing the phospholipid, which is readily available in synthetic form, but replacing the apoprotein component, more specifically, its unique biophysical properties rather than its chemistry. The potential of amphiphilic reactive hypercoiling behaviour of poly(styrene-alt-maleic acid) (PSMA) was studied in combination with two diacylphosphatidylcholines (PC) of different chain lengths in aqueous solution. The surface properties of the mixtures were characterized by conventional Langmuir-Wilhelmy balance (surface pressure under compression) and the du Nouy tensiometer (surface tension of the non-compressed mixtures). Surface tension values and 31P NMR demonstrated that self-assembly of polymer-phospholipid mixtures were pH and concentration-dependent. Finally, the particle size and zeta potential measurements of this self-assembly showed that it can form negatively charged nanosized structures that might find use as drug or lipids release systems on interfaces such as the tear film or lung interfacial layers. The structural reorganization was sensitive to the alkyl chain length of the PC.

Summary The Bombyx mori silk fibroin (SF) has recently received much attention as promising hydrogel matrices due to its biocompatibility, hydrophilicity and good permeability. Beside these, porous SF is too brittle in its dry state that does not provide sufficient strength for practical use. To overcome this drawback, semi-interpenetrating networks of SF were synthesized by a redox-initiated reaction using poly(ethylene glycol) diacrylate (PEGa) as a precursor to form a primary network. Various hydrogel properties, including swelling ability, gelation kinetics, morphology and drug release, were evaluated through both physical and spectroscopic techniques. For all hydrogels, the gelation time, sol-gel fraction and equilibrium water content (EWC) were found to decrease with the increasing of PEGa content. Moreover, a sustained delivery of a model compound, Rhodamine B, was also observed. This could be explained in terms of tighter interconnected network and the retardation effects mediated by SF. The proposed method had thus, demonstrated its potential use to improve performance of silk-based materials for drug delivery applications.

Summary Silk fibroin (SF) hydrogels has recently been explored as promising matrices for biomedical applications due to their excellent biodegradability, biocompatibility and hydrophilicity. Despite these, native SF hydrogels showed poor water resistance with typical uncontrollable gelation kinetics. To overcome these drawbacks, a new method of chemical crosslinking using O'O-bis[2-(N-succinimidyl succinylamino) ethyl]polyethylene glycol (NHSP) as a homobifunctional protein crosslinker was employed. A crosslinking reaction, performed under physiological conditions, was completed within 24 hours, producing a hybrid interconnected porous architecture. This network formation contributed to the shortened gelation kinetics and was confirmed by the appearance of a new IR absorption peak of the ether linkage (1102–1104 cm−1). A new thermal degradation temperature found at 430 °C also reconfirmed the presence of such newly-formed covalent network within the samples. In addition, NHSP could induce a silk phase transformation from the α-helices into the β-sheets, as convinced by the shifts of the amide absorption bands (Amide I, Amide II and Amide III), illustrating their strong intermolecular interactions. The new proposed method has thus, proven its potential use to render the silk-based materials for controlled drug delivery applications.

Nowadays, bio-plastic is the most popular in packaging field. Green chemistry and environmental responsibility has led it to develop the bio-plastic for use as packaging. Polylactic acid (PLA) is the well known staring material in this area. However, some properties of PLA films have to develop. Polymer blend is the interesting technique, in this work, PLA/Cellulose acetate (CA) blend films were prepare by casting solution at various compositions. Mixing solvent of Chloroform and acetone in acid condition were used, it was found that the mixing solvent can improved the compatibility and mechanical properties of the blend films. From this work CA can significantly increase PLA properties both the usefulness and the possible applications for bio-plastic material.

Hypercoiling poly (styrene-alt-maleic anhydride) (PSMA) is known to undergo conformational transition in response to environmental stimuli. This behavior allows it to associate with the phospholipid,2-dilauryl-sn-glycero-3-phosphocholine (DLPC) to produce nanostructures analogous to lipoproteins. The complex represents a new bio-mimetic delivery vehicle with applications in the cosmetic and pharmaceutical industries. This study investigates, for the first time, the association behavior of PSMA and DLPC through the combination of different analytical techniques. The results indicate that the association is primarily driven by hydrophobic interactions and depends on various factors including the polymer/lipid ratio, the polymer molecular weight and the pH of the aqueous environment. The conformational transition of PSMA leads to the formation of discrete micellar complexes involving anisotropic-to-isotropic lipid phase transformation. As the number of hydrophobic moieties in the polymer is increased, the pH-dependent conformational transition of the polymer plays less important part in achieving this phase transition of the lipid.