Binding Bacteria to Highly Branched Poly(N-isopropyl acrylamide) Modified with Vancomycin Induces the Coil-to-Globule Transition

Abstract

Binding of highly branched poly(N-isopropylacrylamide) with vancomycin end groups to Staphylococcus aureus induced a coil-to-globule phase transition. The polymers aggregated this gram-positive bacteria (but not gram-negative bacteria) over a wide range of temperatures, but cooling to 24-26 degrees C progressed the polymer-bound bacteria through a globule-to-coil phase transition, after which the bacteria were released.

Multi-responsive fluorescence of amphiphilic diblock copolymer containing carboxylate azobenzene and N-isopropylacrylamide

“…In recent years, researches on stimulus-responsive polymers have gained increasing attention for their potential applications as biological sensors [1,2], fluorescence probes [3,4], and drug controlled delivery [5e7]. Environmental stimuli such as light [8], pH [9], temperature [10], humidity [11], CO 2 [12,13] and electric/ magnetic field [14] can induce conformational and/or soluble changes of segments of chains at molecular level.…”

Glutathione-triggered disassembly of isothermally responsive polymer nanoparticles obtained by nanoprecipitation of hydrophilic polymers

“…7 Ester and amide linkages are routinely employed for this purpose as they slowly hydrolyse in biological milieu with the assistance of ester-/peptid-ases. For example, Harth and co-workers have reported cross-linked polyesters with potential for intracellular 30 delivery. [8][9] These particles have been used to entrap high concentrations of hydrophobic therapeutics whilst displaying linear degradation characteristics dependent on their crystallinity.…”

“…This enabled the soluble-insoluble transition associated with an LCST to be manipulated using biochemical-triggers rather than temperature 75 changes, an "isothermal" transition. [24][25][26][27] Other examples of isothermal responses include the use of salt gradients, 28 redoxactive spin labels 29 and bacterial binding, 30 the key advantage of which is that known responsive polymers can be easily modified to initiate complex responses under more biologically relevant 80 conditions. The incorporation of redox and thermally responsive components into nanoparticles via complex block copolymer self-assembly is particularly challenging from a synthetic perspective.…”

“…This will allow the particle solubility to switch, triggering disassembly and cargo release using only end-group reduction events rather than random degradation of the polymer backbone. Furthermore, the released 30 polymer will be hydrophilic and of sufficiently low molecular weight to be removed by renal elimination, without the need for polymer degradation (Figure 1). In this study poly(N-isopropylacrylamide), PNIPAM, was selected as the responsive polymer given its strong shift in cloud point (measurable property of the LCST) upon polymer endgroup modification provides the desired 'solubility release 40 catch'.…”

Photochemical Switching of the Phase‐Transition Temperatures of p‐NIPAM–Pt Nanoparticles Thermosensitive Polymer Composites Associated with Electrodes: Functional Electrodes for Switchable Electrocatalysis

“…[15] Also, the effects of pH, [16] added salt, [17] organic solvents, [18] and copolymer units [19] on the phase-transition temperature have been examined. Different applications of the thermosensitive p-NIPAM matrices have been suggested, including controlled drug delivery, [20] controlled biocatalysis, [21] separation, [22] biological applications, such as delivery of cells, [23] culturing of cells, [24] bacteria-induced changes of the polymer structures, [25] and their use as nanothermometers. [26] Also, the incorporation of coadditives into p-NIPAM has been found to affect the phase-transition temperatures of the polymer matrices.…”