Stimuli‐Responsive Surfaces in Biomedical Applications

Abstract

Nature provides mechanisms that are able to dynamically control specific and nonspecific interactions between cells and biological surfaces [1,2]. Scientists have long tried to reproduce these dynamic biological events and have recently made an important step in that direction by creating artificial stimuli-responsive surfaces [3][4][5][6][7]. These smart substrates present modulatory surface properties that are able to respond to external chemical/biochemical [8][9][10][11][12], thermal [13][14][15], electrical [16][17][18][19][20], and optical stimuli [21][22][23][24][25][26][27][28][29][30][31]. Due to their dynamic nature such substrates are very appealing for applications in the biomedical field [32]. Progress to date has led to control over biomolecule activity [33] and immobilization of a diverse array of proteins, including enzymes [34] and antibodies [35]. These prior achievements have encouraged researchers to take the challenge of using dynamic surfaces to modulate larger and more complex systems, such as bacteria [36] and mammalian cells [37].Achieving control over surface properties could provide new insights in the understanding of cell behavior and can offer distinct benefits with regard to the development of medical devices. For instance, the modulation of cell attachment and detachment could lead to the prevention of unwanted bacteria fouling on implants, reducing the risk of infections and rejection [38][39][40][41][42]. Furthermore, dynamic surfaces able to present on demand regulatory signals to a cell could provide unprecedented opportunities in studies of cell responses in real-time. Cells in tissues adhere to and interact with their extracellular environment via specialized cell-cell and cell-extracellular

A Photoresponsive Surface Covalent Organic Framework: Surface‐Confined Synthesis, Isomerization, and Controlled Guest Capture and Release

“…Surfaces that can respond to external stimuli are crucial in the development of functional materials. The past decade has witnessed significantly increased research activities and achievements in the field of smart surfaces . The basic design strategy is to induce reversible structural changes by application of an external stimulus with intent to achieve reversible changes in function.…”

“…The past decadeh as witnessed significantly increased research activities and achievements in the field of smart surfaces. [1,2] The basic designs trategy is to induce reversible structuralc hanges by application of an externals timulus with intent to achieve reversible changes in function. Thec ombined efforts of the molecular synthesis, supramolecular chemistry,a nd surface-science communities have led to exciting opportunities in the development of dynamic, reversibly switchable surfaces, which can be applied in the field of moleculars witchesa nd motors,b iological sensors etc.…”

Reversible Local and Global Switching in Multicomponent Supramolecular Networks: Controlled Guest Release and Capture at the Solution/Solid Interface

“…The combined efforts of molecular synthesis, supramolecular chemistry and surface science community have led to exciting opportunities in the development of dynamic, reversibly switchable surfaces with potential applications in molecular switches and motors, biological sensors, tunable filtration membranes and drug delivery vehicles. [1][2][3][4] Chemisorbed self-assembled monolayers, bilayers, polymers, and semiconductor metal oxide thin films have been employed as active components in the design of switchable surfaces. For organic surfaces, the molecular or macromolecular entities are covalently attached onto a solid surface and their response to external stimuli such as light, heat, pH, surface potential etc.…”

“…The past decade has witnessed significantly increased research activity in the field of smart surfaces, where the fundamental objective is to induce reversible structural changes in supramolecular surfaces by application of an external trigger with an intent to achieve reversible changes in function. The combined efforts of the molecular synthesis, supramolecular chemistry, and surface science community have led to exciting opportunities in the development of dynamic, reversibly switchable surfaces with potential applications in molecular switches and motors, biological sensors, tunable filtration membranes, and drug delivery vehicles. − …”

Dynamic Supramolecular Template: Multiple Stimuli-Controlled Size Adjustment of Porous Networks

“…Self-assembled monolayers (SAMs) offer versatile possibilities in the modification of functional surfaces, − providing ideal templates to explore host–guest phenomena with molecular precision. − Adjustment of morphology and functionalization of porous networks play a key role in exploring host–guest phenomena for their applications in intelligent membranes, biosensors, molecular switches, and drug delivery vehicles. − As for physisorbed monolayers, adsorbate–substrate and adsorbate–adsorbate interactions are noncovalent interactions, such as hydrogen bonds, metal–organic coordination interactions, − van der Waals interactions, − and dipolar coupling, offering more flexibility in structural response to external stimuli. So far, typical stimuli investigated in previous studies include light, − temperature, − solvent, − concentration, − electric field, − and guest molecules. , …”