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Direct neuronal reprogramming of somatic cells into induced neurons (iNs) has been recently established as a promising approach to generating neuron cells. Previous studies have reported that the biophysical cues of the

A scaffold was fabricated to synergistically encapsulate living human adipose-derived stem cells (hASCs) and platelet-rich plasma (PRP) based on a vapor-phase sublimation and deposition process. During the process, ice templates were prepared using sterile water as the solvent and were used to accommodate the sensitive living cells and PRP molecules. Under controlled processing conditions, the ice templates underwent vapor sublimation to evaporate water molecules, while at the same time, vapor-phase deposition of poly

In this study, a porous, three-dimensional material of parylene (poly-p-xylylene) incorporating keratin was fabricated. As an FDA-approved material, parylene is highly stable and biocompatible. Ker...

The surface properties of biomaterials are crucial at controlling biological interactions. Cells or tissues sense different stimuli from surfaces and respond accordingly. A number of studies have reported that fabricating complex stimuli-presenting surfaces is beneficial for mimicking and understanding the in vivo scenario where multi-physicochemical cues are present. Biological responses toward these surfaces could be either negative, such as immune responses, or positive, such as tissue regeneration. An ideal material surface should, therefore, be multifunctional, triggering the desired biological process and suppressing the unwanted side effects. The methods for material surface decoration can be very sophisticated, depending on the applications such as biosensors, medical devices, and/or implants. To date, decorating material surfaces with complex chemistries and topographies is still challenging, and methods are not straightforward. The majority of the methods require multiple steps and combinational approaches that include mask-based techniques, lithography, wet or dry etching, wet chemistry, or vapor-based coatings, among others. Although these methods have been established in the laboratory, easy-to-access and straightforward approaches need to be explored. This Review summarizes the state-of-the-art techniques for generating patterned multichemical and multitopographic signals on material surfaces, and the potential of having these surfaces in biointerface applications.

An elegant and precise method to fabricate asymmetrical structures and/or gradient structures was developed based on a vapor-phase sublimation and deposition process. The fabricated materials exhib...

Bottom–up approaches using building blocks of modules to fabricate scaffolds for tissue engineering applications have enabled the fabrication of structurally complex and multifunctional materials allowing for physical and chemical flexibility to better mimic the native extracellular matrix. Here we report a vapor-phased fabrication process for constructing three-dimensional modulated scaffold materials via simple steps based on controlling mass transport of vapor sublimation and deposition. We demonstrate the fabrication of scaffolds comprised of multiple biomolecules and living cells with built-in boundaries separating the distinct compartments containing defined biological configurations and functions. We show that the fabricated scaffolds have mass production potential. We demonstrate overall >80% cell viability of encapsulated cells and that modulated scaffolds exhibit enhanced cell proliferation, osteogenesis, and neurogenesis, which can be assembled into various geometric configurations. We perform cell co-culture experiments to show independent osteogenesis and angiogenesis activities from separate compartments in one scaffold construct., Current methods for the modular assembly of biomaterials are associated with limitations. Here the authors implement vapor-phase deposition to fabricate 3D polymeric materials that permit biomolecule functionalization, tunable mass transport and mechanical properties, as well as control over boundaries between compartments, and analyze the behavior of 3D encapsulated cells.

Surface modification layers are performed on the surfaces of biomaterials and have exhibited promise for decoupling original surface properties from bulk materials and enabling customized and advanced functional properties. The physical stability and the biological compatibility of these modified layers are equally important to ensure minimized delamination, debris, leaching of molecules, and other problems that are related to the failure of the modification layers and thus can provide a long-term success for the uses of these modified layers. A proven surface modification tool of the functionalized poly-para-xylylene (PPX) system was used as an example, and in addition to the demonstration of their chemical conjugation capabilities and the functional properties that have been well-documented, in the present report, we additionally devised the characterization protocols to examine stability properties, including thermostability and adhesive strength, as well as the biocompatibility, including cell viability and the immunological responses, for the modified PPX layers. The results suggested a durable coating stability for PPXs and firmly attached biomolecules under these stability and compatibility tests. The durable and stable modification layers accompanied by the native properties of the PPXs showed high cell viability against fibroblast cells and macrophages (MΦs), and the resulting immunological activities created by the MΦs exhibited excellent compatibility with non-activated immunological responses and no indication of inflammation.

A prospective design for interface properties is enabled to perform precise functionalization, erasure capability for existing properties, reactivation of surface functionality to a second divergent property. A vapor-deposited, 2-nitro-5-(prop-2-yn-1-yloxy)methylbenzyl carbamate-functionalized poly-para-xylylene coating is synthesized in this study to realize such tasks by offering the accessibility of the azide/alkyne click reaction, an integrated photochemical decomposition/cleavage moiety, and the reactivation sites of amines behind the cleavage that allow the installation of a second surface function. With the benefits from the mild processing conditions used for the coatings and the rapid response of the photochemical reaction, the creation of sophisticated interface properties and localized chemical compositions was elegantly demonstrated with a hybrid functionality including a confined hydrophlic/hydrophobic wetting property and/or a cell adherent/repellent platform on such a coating surface.

The field of implantable electronics relies on using silicon materials due to the merits of a well-established fabrication process and favorable properties; of particular interest is the surface modification of such materials. In the present study, we introduce a surface modification technique based on coatings of functionalized Parylene on silicon substrates, where the modified layers provide a defined cell adhesion capability for the resultant silicon materials/devices. Functionalization of Parylene was achieved during a one-step chemical vapor deposition (CVD) polymerization process, forming NHS ester-functionalized Parylene, and subsequent RGD attachment was enabled via a conjugation reaction between the NHS ester and amine groups. The modification procedures additionally provided a clean and gentle approach to avoid thermal excursions, intense irradiation, chemicals, or solvents that might damage delicate structures or sensitive molecules on the devices. The modification layers exhibited excellent mechanical strength on the substrate, meeting the high standards of the American Society for Testing and Materials (ASTM), and the resultant cell adherence property was verified by a centrifugation assay and the analysis of attached cell morphologies; the results collectively demonstrated robust and sustainable modification layers of the NHS ester-functionalized Parylene and confirmed that the cell-adherence property imparted by using this facile modification technique was effective. The modification technology is expected to benefit the design of prospective interface properties for silicon-based devices and related industrial products.

Surface modification with functional materials, such as anti-fouling or thermal responsive polymers, on biomedical devices benefits their clinical performance. Simple and versatile technologies, which could be applied to a wide variety of substrates, are still highly desirable. Chemical vapor deposition (CVD) of 4-benzoyl-[2,2]paracyclophane (Benzoyl-PPX) layers attracts much attention because the photoreactive platform could be deposited onto almost every substrate for the conjugation of functional molecules. In this study, poly(ethylene glycol) (PEG) was conjugated onto Benzoyl-PPX via UV illumination. The deposited PEG films could effectively reduce protein adsorption and cell attachment. The low-fouling properties of the PEG films were positively correlated with the molecular weight and concentration of PEG. We found that a PEG film, thicker than 16 nm and with a water contact angle of 30°, is a prerequisite for effective inhibition of cell attachment. We also demonstrated that the PEG coating was stable under acidic and basic environments. Furthermore, poly(N-isopropyl acrylamide), PNIPAAm, could be also tethered on the Benzoyl-PPX via UV illumination, and possessed thermal-responsive properties. Intact cell sheets could be released from the PNIPAAm film by decreasing culture temperature. The results indicate that Benzoyl-PPX is an excellent photoreactive platform for the conjugation of functional polymers for modulation of cell attachment.

Modifications of biomaterials based on the combination of physical, chemical, and biological cues for manipulating stem cell growth are needed for modern regenerative medicine. The exploitation of these sophisticated modifications remains a challenge, including substrate limitation, biocompatibility, and versatile and general cues for stem cell activities. In this report, a vapor-phase coating technique based on the functionalization of poly-p-xylylene (PPX) was used to generate a surface modification for use with stem cells in culture. The coating provided the ability for covalent conjugation that immobilized bone morphogenetic protein 2 (BMP-2) and fibroblast growth factor 2 (FGF-2), and the modified coating surfaces enabled direct stem cell differentiation and controlled proliferation because of the specific activities. The ligations were realized between the growth factors and the maleimide-modified surface, and the conjugation reactions proceeded with high specificity and rapid kinetics under mild conditions. The conjugation densities were approximately 140 ng·cm−2 for BMP-2 and 155 ng·cm−2 for FGF-2. Guiding the activities of the human adipose-derived stem cells (hADSCs) was achieved by modifying surfaces to promote the hADSC differentiation capacity and proliferation rate. The reported coating system demonstrated biocompatibility, substrate-independent conformity, and stability, and it could provide an effective and versatile interface platform for further use in biomedical applications.

A vapor-phase process, involving the sublimation of an ice substrate/template and the vapor deposition of a maleimide-functionalized poly-p-xylylene, has been reported to synthesize an advanced porous material, with readily clickable chemical interface properties, to perform a Michael-type addition of a maleimide functionality for conjugation with a thiol group. In contrast to the conventional chemical vapor deposition of poly-p-xylylenes on a solid surface that forms thin film coatings, the process reported herein additionally results in deposition on a dynamic and sublimating ice surface (template), rendering the construction of a three-dimensional, porous, maleimide-functionalized poly-p-xylylene. The process seamlessly exploits the refined chemical vapor deposition polymerization from maleimide-substituted [2,2]paracyclophane and ensures the preservation and transformation of the maleimide functionality to the final porous poly-p-xylylene products. The functionalization and production of a porous maleimide-functionalized poly-p-xylylene were completed in a single step, thus avoiding complicated steps or post-functionalization procedures that are commonly seen in conventional approaches to produce functional materials. More importantly, the equipped maleimide functionality provides a rapid and efficient route for click conjugation toward thiol-terminated molecules, and the reaction can be performed under mild conditions at room temperature in a water solution without the need for a catalyst, an initiator, or other energy sources. The introduced vapor-based process enables a straightforward synthesis approach to produce not only a pore-forming structure of a three-dimensional material, but also an in situ-derived maleimide functional group, to conduct a covalent click reaction with thiol-terminal molecules, which are abundant in biological environments. These advanced materials are expected to have a wide variety of new applications.

Conventional porous materials are mostly synthesized in solution-based methods involving solvents and initiators, and the functionalization of these porous materials usually requires additional and complex steps. In the current study, a methyl propiolate-functionalized porous poly-p-xylylene material was fabricated based on a unique vapor sublimation and deposition process. The process used a water solution and ice as the template with a customizable shape and dimensions, and the conventional chemical vapor deposition (CVD) polymerization of poly-p-xylylene on such an ice template formed a three-dimensional, porous poly-p-xylylene material with interconnected porous structures. More importantly, the functionality of methyl propiolate was well preserved by using methyl propiolate-substituted [2,2]-paracyclophane during the vapor deposition polymerization process and was installed in one step on the final porous poly-p-xylylene products. This functionality exhibited an intact structure and reactivity during the proposed vapor sublimation and deposition process and was proven to have no decomposition or side products after further characterization and conjugation experiments. The electron-withdrawing methyl propiolate group readily provided efficient alkynes as click azide-terminated molecules under copper-free and mild conditions at room temperature and in environmentally friendly solvents, such as water. The resulting methyl propiolate-functionalized porous poly-p-xylylene exhibited interface properties with clickable specific covalent attachment toward azide-terminated target molecules, which are widely available for drugs and biomolecules. The fabricated functional porous materials represent an advanced material featuring porous structures, a straightforward synthetic approach, and precise and controlled interface click chemistry, rendering long-term stability and efficacy to conjugate target functionalities that are expected to attract a variety of new applications.

An innovative chemical vapor sublimation and deposition (CVSD) process was shown to produce nanoscale anisotropic hybrid materials. Taking advantage of controlled thermodynamic properties and the mass transfer of molecules, this process allowed for water vapor sublimation from an iced template/substrate and stagewise vapor deposition of poly-p-xylylene onto the sublimating ice substrate. In this study, the use of sensitive soybean agglutinin (SBA) protein tubes was demonstrated as an example to prepare the anisotropic hybrid material based on the CVSD process. The rationale of a timing parameter, &Delta, t, was controlled to program the sublimation of the SBA-ice templates and the deposition of poly-p-xylylene during the CVSD process. As a result of this control, a stripping stage occurred, during which SBA tubes were exposed on the particle surface, and a subsequent encapsulation stage enabled the transformation of the ice templates into a nanometer-sized anisotropic hybrid material of poly-p-xylylene as the matrix with encapsulated SBA tubes. The timing parameter &Delta, t and the controlled stripping and encapsulating stages during CVSD represent a straightforward and intriguing mechanism stemming from physical chemistry fundamentals for the fabrication of hybrid materials from sensitive molecules and with predetermined sizes and asymmetrical shapes. A simulation analysis showed consistency with the experimental results and controllability of the timing mechanism with predictable particle sizes.

Advanced antibacterial surfaces are designed based on covalently attached antibacterial agents, avoiding potential side effects associated with overdosed or eluted agents. The technique is widely applicable regardless of the underlying substrate material. In addition, antibacterial surfaces are effective against the early stages of bacterial adhesion and can significantly reduce the formation of biofilm, without compromising biocompatibility. Here, this concept was realized by employing a benzoyl-functionalized parylene coating. The antibacterial agent chlorhexidine was used as a proof of concept. Chlorhexidine was immobilized by reaction with photoactivated benzoyl-functionalized surfaces, including titanium alloy, stainless steel, polyether ether ketone, polymethyl methacrylate, and polystyrene. A low concentration of chlorhexidine (1.4 ± 0.08 nmol cm−2) covalently bound to surfaces rendered them sufficiently resistant to an Enterobacter cloacae inoculum and its adherent biofilm. Compared to unmodified surfaces, up to a 30-fold reduction in bacterial attachment was achieved with this coating technology. The immobilization of chlorhexidine was verified with infrared reflection absorption spectroscopy (IRRAS) and X-ray photoelectron spectroscopy (XPS), and a leaching test was performed to confirm that the chlorhexidine molecules were not dislodged. Cell compatibility was examined by culturing fibroblasts and osteoblasts on the modified surfaces, revealing greater than 93% cell viability. This coating technology may be broadly applicable for a wide range of other antibacterial agents and allow the design of new biomaterials.

An advanced material interface is modified by using a substrate-independent coating of detachable poly-para-xylylene, enabling dynamical control of the immobilization and detachment of biomolecules, and a previously installed biological function is deactivated or tuned with reduced activity. The induction of osteogenesis activity, and subsequent deactivation of such osteogenesis activity, is demonstrated.

Surface coatings are critical in biomaterials and biomedical devices. Chemical vapor deposition (CVD) is a well-known technology for the generation of thin films on a surface. However, the granular structures produced using CVD are rare. Recently, we used PPX-C, an excellent insulating material, for granular structure coating using CVD. Colloidal self-assembly is also a well-established method to generate granular structures named colloidal self-assembled patterns (cSAPs). In this study, we combined these two technologies to generate hierarchical granular structures and tested the biophysical effect of these hybrid surfaces on human bone marrow mesenchymal stem cells (hBMSCs). Two CVD-derived granular structures were made using water or glycerin droplets (i.e., CVD or GlyCVD surfaces). Water drops generate porous particles, while glycerin drops generate core–shell particles on the surface. These particles were dispersed randomly on the surface with sizes ranging from 1 to 20 μm. These CVD surfaces were hydrophobic (WCA ~ 80–110 degrees). On the other hand, a binary colloidal crystal (BCC), one type of cSAPs, composed of 5 μm Si and 400 nm carboxylated polystyrene (PSC) particles, had a close-packed structure and a hydrophilic surface (WCA ~ 45 degrees). The hybrid surfaces (i.e., CVD-BCC and GlyCVD-BCC) were smooth (Ra ~ 1.1–1.5 μm) and hydrophilic (WCA ~ 50 degrees), indicating a large surface coverage of BCC dominating the surface property. The hybrid surfaces were expected to be slightly negatively charged due to naturally charged CVD particles and negatively charged BCC particles. Cell adhesion was reduced on the hybrid surfaces, leading to an aggregated cell morphology, without reducing cell activity, compared to the flat control after 5 days. qPCR analysis showed that gene expression of type II collagen (COL2) was highly expressed on the GlyCVD-BCC without chemical induction after 3 and 14 days compared to the flat control. This proof-of-concept study demonstrates the potential of combining two technologies to make hybrid structures that can modulate stem cell attachment and differentiation.

Surface modification layers are needed for the precise definition of surface chemistries and are equally important for durable and stable adhesive properties to ensure long-term stability and effective performance for biotechnological applications. This study demonstrates a robust modification layer that is synthesized based on chemical vapor deposition copolymerization, and the resultant coating layer is composed of the side-by-side presentation of N-hydroxysuccinimide ester and maleimide functionalities with a controlled ratio to define the immobilization accessibility of chitosan and growth factor protein (FGF-2) molecules on the substrate surface for enhancing cellular activities of stem cells. Characterizations of the copolymer modification layer showed excellent durability, including adhesive strength and thermal stability, and the layer is free of concerns for delamination and/or unacceptable deformation/debris formation that can cause potential toxicity to the surrounding biological environment. Modifications using the copolymer layer on the cell culture surface have demonstrated synergistic activity by chitosan to support the formation of spheroids and by FGF-2 to enhance the proliferation of human adipose-derived stem cells (ADSCs) within the spheroids while increasing the spheroid size and cell numbers. Healthy and flourishing growth activities were discovered for ADSCs on the modified culture surfaces, and the results are useful for potential and related stem cell research and the interfaces of biomaterials.

We report a vapor-phase deposition of poly(p-xylylene) (parylene) membranes for gas separations. Three parylene membranes, poly[(2-chloro-p-xylylene)] (parylene C), poly[(4-amino-p-xylylene)-co-(p-xylylene)] (parylene A), and poly[(2-carboxylic acid N-hydroxysuccinimide ester)-co-(p-xylylene)] (parylene NHS ester), were evaluated. These membranes were deposited on a support of porous poly(vinylidene fluoride) with a dense layer of poly(vinyl alcohol) cast on its top surface. The as-synthesized parylene membranes were characterized by scanning electron microscopy, FT-IR spectroscopy, and the measurements of water contact angle. Single-gas permeation with hydrogen, nitrogen, methane, and carbon dioxide was performed on the parylene membranes for assessing their molecular transport properties. These parylene membranes showed gas permeability of up to hundreds of barrer. To further enhance the gas separation performance of the parylene membranes, polyethylenimine (PEI) was used for modifying the surface of the membranes composed of parylene NHS ester.

Three-dimensional porous structures are constructed via vapor deposition onto a sublimating solid template. Construction upon deposition of vapor-phase material occurs at a dynamic vapor–solid interface and is directed by the solid surface vanishing by sublimation. A proof-of-concept demonstration showed vapor depositions of poly- para -xylylenes (PPXs) on sublimating templates, including ice and mixtures with ethanol and hexane. The material construction macroscopically produces a replica architecture of the parent template. Characteristics of the pore structures are formed during the construction process as a result of the gas vapor and the space that is vacated by sublimation, thus enabling control of the porosity through regulation of the sublimation speed and/or the thermodynamic properties of the templates. The technology introduced herein provides a novel approach for 3D porous material manufacturing and overturns the notion that vapor deposition necessarily forms dense thin films on substrates.

Multifunctional nanoparticles featuring three distinct and orthogonal functionalities for performing catalyst-free click reactions of azide-alkyne and maleimide-thiol and atom transfer radical polymerization (ATRP) are fabricated using a simple chemical vapor deposition copolymerization approach with the flexibility to control the particle size and geometry.

An erasable coating was prepared to modify material surfaces with accessibilities, including specific conjugation, elimination of the conjugated chemistry/function, and the reactivation of a second new chemistry/function. The coating was realized based on a vapor-deposited functional poly-p-xylylene coating composed of an integrated 3-((3-methylamido)-disulfanyl)propanoic acid functional group, resulting in not only chemical reactivity, but also a disulfide interchange mechanism. Mechanically, the coating was robust in terms of the thermal stability and adhesive property on a variety of substrate materials. Chemically, the anchoring site of carboxylic acid was accessible for specific conjugation, and a disulfide bridge moiety was used to disengage already installed functions/properties. In addition, the homogeneous nature of the vapor-phased coating technique is known for its morphology/thickness and distribution of the functional moiety, which allowed precision to address the installation or erasure of functions and properties. Characterization of the precisely confined hydrophilic/hydrophobic wetting property and the alternating reversibility of this wetting property on the same surface was achieved.

The success of recent material science and applications in biotechnologies should be credited to developments of malleable surface properties, as well as the adaptation of conjugation reactions to the material surface [...]

A regulatable bioremediation capsule material was synthesized with isolated single-strain bacteria (Bacillus species, B. CMC1) and a regulator molecule (carboxymethyl cellulose, CMC) by a vapor-phased encapsulation method with simple steps of water sublimation and poly-p-xylylene deposition in chemical vapor deposition (CVD) process. Mechanically, the capsule construct exhibited a controllable shape and dimensions, and was composed of highly biocompatible poly-p-xylylene as the matrix with homogeneously distributed bacteria and CMC molecules. Versatility of the encapsulation of the molecules at the desired concentrations was achieved in the vapor-phased sublimation and deposition fabrication process. The discovery of the fabricated capsule revealed that viable living B. CMC1 inhabited the capsule, and the capsule enhanced bacterial growth due to the materials and process used. Biologically, the encapsulated B. CMC1 demonstrated viable and functional enzyme activity for cellulase activation, and such activity was regulatable and proportional to the concentration of the decorated CMC molecules in the same capsule construct. Impressively, 13% of cellulase activity increase was realized by encapsulation of B. CMC1 by poly-p-xylylene, and a further 34% of cellulase activity increase was achieved by encapsulation of additional 2.5% CMC. Accordingly, this synergistic effectiveness of the capsule constructs was established by combining enzymatic B. CMC1 bacteria and its regulatory CMC by poly-p-xylylene encapsulation process. This reported encapsulation process exhibited other advantages, including the use of simple steps and a dry and clean process free of harmful chemicals, most importantly, the process is scalable for mass production. The present study represents a novel method to fabricate bacteria-encapsulated capsule for cellulose degradation in bioremediation that can be used in various applications, such as wastewater treatment and transforming of cellulose into glucose for biofuel production. Moreover, the concept of this vapor-phased encapsulation technology can be correspondingly used to encapsulate multiple bacteria and regulators to enhance the specific enzyme functions for degradation of various organic matters.

A surface resisting protein adsorption and cell adhesion is highly desirable for many biomedical applications such as diagnostic devices, biosensors and blood-contacting devices. In this study, a surface conjugated with sulfobetaine molecules was fabricated via the click reaction for the anti-fouling purpose. An alkyne-containing substrate (Alkyne-PPX) was generated by chemical vapor deposition of 4-ethynyl- [2,2]paracyclophane. Azide-ended mono-sulfobetaine molecules were synthesized and then conjugated on Alkyne-PPX via the click reaction. The protein adsorption from 10% serum was reduced by 57%, while the attachment of L929 cells was reduced by 83% onto the sulfobetaine-PPX surface compared to the protein adsorption and cell adhesion on Alkyne-PPX. In conclusion, we demonstrate that conjugation of monosulfobetaine molecules via the click chemistry is an effective way for reduction of non-specific protein adsorption and cell attachment.

In this study, poly-para-xylylene-based multifunctional nanoparticles (PPX-NPs) were fabricated. Based on the solubility characteristics determined for asymmetrically substituted poly-para-xylylenes in polar solvents, well-dispersed nanocolloids with a controllable size ranging from 50 to 800nm were produced in solution by the displacement of the solvent (water). These size ranges were found to have acceptable cellular compatibility through examinations of cultured 3T3 fibroblasts and adipose-derived stem cells treated with the PPX-NPs. In addition, these nanoscale PPX-NPs exhibited versatile bioconjugation properties in that a variety of available functional groups can be adopted from their counterpart, thin-film poly-para-xylylenes, during the production of these nanoparticles. For instance, bifunctional PPX-NPs with maleimide and benzoyl moieties were produced to enable immobilization via a maleimide-thiol reaction concurrent with a photochemical reaction. A cleavable PPX-NP was also produced with a thiol-exchangeable surface property. Additionally, by performing electrohydrodynamic jetting of parallel polymer solutions of selected poly-para-xylylenes, Janus-type or multicompartment PPX-NPs were created. The PPX-NPs can potentially be used for various biomedical applications such as combined diagnostics and drug delivery, multiplexing of detection, multiple-drug loading, and the targeted delivery of biomolecules or drugs.

"Click" reactions provide precise and reliable chemical transformations for the preparation of functional architectures for biomaterials and biointerfaces. The emergence of a multiple-click reaction strategy has paved the way for a multifunctional microenvironment with orthogonality and precise multitasking that mimics nature. We demonstrate a multifaceted and route-controlled click interface using vapor-deposited functionalized poly-para-xylylenes. Distinctly clickable moieties of ethynyl and maleimide were introduced into poly-para-xylylenes in one step via a chemical vapor deposition (CVD) copolymerization process. The advanced interface coating allows for a double-click route with concurrent copper(i)-catalyzed Huisgen 1,3-dipolar cycloaddition (CuAAC) and the thiol-maleimide click reaction. Additionally, double-click reactions can also be performed in a cascade manner by controlling the initiation route to enable the CuAAC and/or thiol-yne reaction using a mono-functional alkyne-functionalized poly-para-xylylene. The use of multifaceted coatings to create straightforward and orthogonal interface properties with respect to protein adsorption and cell attachment is demonstrated and characterized.

The bottom-up patterning approach provides intrinsic advantages associated with unlimited resolution but is limited by the materials available for selection. A general and simple approach towards the selective deposition of poly-para-xylylenes is introduced in this communication. The chemical vapour deposition (CVD) of poly-para-xylylenes is inhibited on the high-energy surfaces of electrically charged conducting substrates. This technology provides an approach to selectively deposit poly-para-xylylenes irrespective of the substituted functionality and to pattern these polymer thin films from the bottom up.