Thiol-ene Chemistry Research Articles

Alternative Chemistries for Free Radical-Initiated Targeting and Immobilization.

Stimuli-responsive biomaterials are an emerging strategy that leverage common pathophysiological triggers to target drug delivery to limit or avoid toxic side effects. Native free radicals, such as reactive oxygen species (ROS), are widely upregulated in many pathological states. We have previously demonstrated that native ROS are capable of crosslinking and immobilizing acrylated polyethylene glycol diacrylate (PEGDA) networks and coupled payloads in tissue mimics, providing evidence for a potential targeting mechanism. To build on these promising results, we evaluated PEG dialkenes and dithiols as alternative polymer chemistries for targeting. The reactivity, toxicity, crosslinking kinetics, and immobilization potential of PEG dialkenes and dithiols were characterized. Both the alkene and thiol chemistries crosslinked in the presence of ROS, generating high molecular weight polymer networks that immobilized fluorescent payloads in tissue mimics. Thiols were especially reactive and even reacted with acrylates in the absence of free radicals, and this motivated us to explore a two-phase targeting approach. Delivering thiolated payloads in a second phase, after the initial polymer net formation, allowed greater control over the payload dosing and timing. Two-phase delivery combined with a library of radical-sensitive chemistries can enhance the versatility and flexibility of this free radical-initiated platform delivery system.

3D high-precision melt electro written polycaprolactone modified with yeast derived peptides for wound healing

In this study melt electro written (MEW) scaffolds of poly(ε-caprolactone) PCL are decorated with anti-inflammatory yeast-derived peptide for skin wound healing. Initially, 13 different yeast-derived peptides were screened and analyzed using both in vitro and in vivo assays.The MEW scaffolds are functionalized with the selected peptide VLSTSFPPW (VW-9) with the highest activity in reducing pro-inflammatory cytokines and stimulating fibroblast proliferation, migration, and collagen production. The peptide was conjugated to the MEW scaffolds using carbodiimide (CDI) and thiol chemistry, with and without plasma treatment, as well as by directly mixing the peptide with the polymer before printing. The MEW scaffolds modified using CDI and thiol chemistry with plasma treatment showed improved fibroblast and macrophage penetration and adhesion, as well as increased cell proliferation and superior anti-inflammatory properties, compared to the other groups. When applied to full-thickness excisional wounds in rats, the peptide-modified MEW scaffold significantly enhanced the healing process compared to controls (p < 0.05). This study provides proof of concept for using yeast-derived peptides to functionalize biomaterials for skin wound healing.

Thiol-Ene Photo-Click Hydrogels with Tunable Mechanical Properties Resulting from the Exposure of Different -Ene Moieties through a Green Chemistry.

Temperature and light responsiveness are widely exploited stimuli to tune the physico-chemical properties of double network hydrogels. In this work, new amphiphilic poly(ether urethane)s bearing photo-sensitive moieties (i.e., thiol, acrylate and norbornene functionalities) were engineered by exploiting the versatility of poly(urethane) chemistry and carbodiimide-mediated green functionalization procedures. Polymers were synthesized according to optimized protocols maximizing photo-sensitive group grafting while preserving their functionality (approx. 1.0 × 1019, 2.6 × 1019 and 8.1 × 1017 thiol, acrylate and norbornene groups/gpolymer), and exploited to prepare thermo- and Vis-light-responsive thiol-ene photo-click hydrogels (18% w/v, 1:1 thiol:ene molar ratio). Green light-induced photo-curing allowed the achievement of a much more developed gel state with improved resistance to deformation (ca. 60% increase in critical deformation, γL). Triethanolamine addition as co-initiator to thiol-acrylate hydrogels improved the photo-click reaction (i.e., achievement of a better-developed gel state). Differently, L-tyrosine addition to thiol-norbornene solutions slightly hindered cross-linking, resulting in less developed gels with worse mechanical performances (~62% γL decrease). In their optimized composition, thiol-norbornene formulations resulted in prevalent elastic behavior at lower frequency compared to thiol-acrylate gels due to the formation of purely bio-orthogonal instead of heterogeneous gel networks. Our findings highlight that exploiting the same thiol-ene photo-click chemistry, a fine tuning of the gel properties is possible by reacting specific functional groups.

Selected Area Deposition of High Purity Gold for Functional 3D Architectures.

Selected area deposition of high purity gold films onto nanoscale 3D architectures is highly desirable as gold is conductive, inert, plasmonically active, and can be functionalized with thiol chemistries, which are useful in many biological applications. Here, we show that high-purity gold coatings can be selectively grown with the Me2Au (acac) precursor onto nanoscale 3D architectures via a pulsed laser pyrolytic chemical vapor deposition process. The selected area of deposition is achieved due to the high thermal resistance of the nanoscale geometries. Focused electron beam induced deposits (FEBID) and carbon nanofibers are functionalized with gold coatings, and we demonstrate the effects that laser irradiance, pulse width, and precursor pressure have on the growth rate. Furthermore, we demonstrate selected area deposition with a feature-targeting resolutions of ~100 and 5 µm, using diode lasers coupled to a multimode (915 nm) and single mode (785 nm) fiber optic, respectively. The experimental results are rationalized via finite element thermal modeling.

Overexpression and cell-penetrating peptide-mediated delivery of Cas9 and its variant(s) for targeted genome editing.

The clustered, regularly interspaced, short palindromic repeat (CRISPR)-associated (Cas) system is a powerful tool that has been used for genome editing. Cas9 is a bacterial RNA-guided endonuclease that cleaves target DNA and modifies a cell's genome. Despite the advantages and promising results of the use of CRISPR-Cas9 as a molecular tool and potential therapeutic protein, the production and purification of the recombinant Cas9 protein remain a challenge. Following protein expression and purification, delivering the Cas9 protein into the cells is a key concern for many researchers. Typically, Cas9 and gRNA are delivered by using either plasmid or viral vectors. However, the plasmid or viral-mediated delivery triggers an undesirable immune response and leads to uncontrolled integration of the plasmid into the host genome. We envision that direct delivery i.e. conjugating the protein with cell-penetrating peptide (CPP) will lead to endogenous gene editing with reduced off-target effects when compared to the other delivery methods that require a transfection reagent. Our study aims to determine if the vector strains or culture conditions need to be optimized based on different Cas9 variants. Additionally, this study intends at delivering Cas9 derived from Streptococcus pyogenes (SpCas9) and other Cas9 variants into the mouse fibroblasts (NIH3T3 cell line) by conjugating the protein with CPP through thiol chemistry. Therefore, here, we methodically evaluate the expression of recombinant SpCas9 and other Cas9 variants in four different E. coli strains (Rosetta, BL21 (regular), BL21 PlysS, and BL21 star). After optimization of the conditions (temperature and post-induction time), BL21 (DE3) PlysS strain efficiently expressed the SpCas9 protein. Overall, the results of this study will inform optimized methods for CPP-mediated delivery of Cas9.

Tuning of Mechanical Properties in Photopolymerizable Gelatin-Based Hydrogels for In Vitro Cell Culture Systems.

The mechanical microenvironment plays a crucial role in the evolution of colorectal cancer, a complex disease characterized by heterogeneous tumors with varying elasticity. Toward setting up distinct scenarios, herein, we describe the preparation and characterization of gelatin methacrylamide (GelMA)-based hydrogels via two different mechanisms: free-radical photopolymerization and photo-induced thiol-ene reaction. A precise stiffness modulation of covalently crosslinked scaffolds was achieved through the application of well-defined irradiation times while keeping the intensity constant. Besides, the incorporation of thiol chemistry strongly increased stiffness with low to moderate curing times. This wide range of finely tuned mechanical properties successfully covered from healthy tissue to colorectal cancer stages. Hydrogels prepared in phosphate-buffered saline or Dulbecco's modified Eagle's medium resulted in different mechanical and swelling properties, although a similar trend was observed for both conditions: thiol-ene systems exhibited higher stiffness and, at the same time, higher swelling capacity than free-radical photopolymerized networks. In terms of biological behavior, three of the substrates showed good cell proliferation rates according to the formation of a confluent monolayer of Caco-2 cells after 14 days of cell culture. Likewise, a characteristic apical-basal polarization of cells was observed for these three hydrogels. These results demonstrate the versatility of the presented platform of biomimetic materials as in vitro cell culture scaffolds.

Reactive Compatibilization of Impact Copolymer Polypropylene and Organically Modified Mesoporous Silica to Prepare Composites Possessing Enhanced Mechanical Properties

Mesoporous silica was evaluated as functionalized filler in impact copolymer polypropylene (ICP) in its original form as well as after organic modification. Mesoporous silica was synthesized by base-catalyzed hydrolysis of tetraethyl orthosilicate in the water–acetone medium. The organic modification of mesoporous silica was carried out using commercially available silane with a terminal unsaturated bond and by synthesizing silane precursor by chemical treatment via TEMPO-initiated thiol–ene chemistry to introduce alkyl chains terminating in hydroxyl groups. The characterization for all types of mesoporous silica prepared was done using thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FT-IR), solid-state nuclear magnetic resonance spectroscopy, X-ray photoelectron spectroscopy (XPS), Brunauer–Emmett–Teller (BET) analysis, X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), and high-resolution transmission electron microscopy (HR-TEM). ICP–mesoporous silica composites were prepared using 1, 5, and 10 phr mesoporous silica and organically modified mesoporous silica loading via reactive compatibilization and were tested for their thermal, morphological, rheological, and mechanical properties. The addition of mesoporous and organically modified mesoporous silica enhanced thermal stability and nucleation with respect to neat ICP. Tensile and flexural moduli were improved while maintaining their impact strength. Analysis of rheological properties revealed a rise in zero-shear rate viscosity in ICP–mesoporous silica composites. DMA studies showed higher storage and loss modulus with the addition of mesoporous silica in ICP.

Photo‐Patternable Stretchable Semi‐Interpenetrating Polymer Semiconductor Network Using Thiol–Ene Chemistry for Field‐Effect Transistors

AbstractStretchable polymer semiconductors are an essential component for skin‐inspired electronics. However, the lack of scalable patterning capability of stretchable polymer semiconductors limits the development of stretchable electronics. To address this issue, photo‐curable stretchable polymer blends consisting of a high‐mobility donor–acceptor conjugated polymer and an elastic rubber through thiol–ene chemistry are developed. The thiol–ene reaction can selectively cross‐link the rubber with alkene or vinyl groups without damaging the electronic properties of the conjugated polymer. The conjugated polymer chains embedded in the elastic polymer matrix induce a semi‐interpenetrating polymer network (SIPN). The thiol–ene‐cross‐linked network provides great solvent resistance and enhances stretchability for the embedded conjugated polymer. The well‐defined patterned film with a feature size of ≈10 µm can be obtained using UV light at 365 nm through conventional photolithography processes. Furthermore, the SIPN‐based transistors show increased mobilities from 0.61 to 1.18 cm2 V−1 s−1 when applying the strain from 0% to 100%. Moreover, the hole mobility can still maintain at 0.87 cm2 V−1 s−1 after 1000 strain‐and‐release cycles at the strain of 25%. This study sheds light on the molecular design of photo‐curable polymer semiconductors for the mass production of stretchable circuits.

Poly(N-allyl acrylamide) as a Reactive Platform toward Functional Hydrogels.

The synthesis of poly(N-allyl acrylamide) (PNAllAm) as a platform for the preparation of functional hydrogels is described. The PNAllAm was synthesized via organocatalyzed amidation of poly(methyl acrylate) (PMA) with allylamine and characterized by 1H NMR spectroscopy, size exclusion chromatography (SEC), and turbidimetry, which allowed an estimation of the lower critical solution temperature of ∼26 °C in water. The PNAllAm was then used to make functional hydrogels via photoinitiated thiol-ene chemistry, where dithiothreitol (DTT) was used to cross-link the polymer chains. In addition, mercaptoethanol (ME) was added as a functional thiol to modulate the hydrogel properties. A decrease of the volume-phase transition temperature of the resulting hydrogels was observed with increasing ME content. Altogether this work introduces a straightforward way for the preparation of PNAllAm from PMA and demonstrates its value as a reactive polymer platform for the generation of functional hydrogels.

Thiol-ene chemistry incorporates a new spiropyran-containing polyurethane ionogel with photochromic, photomechanical and photoconductive properties.

The photocuring technology based on thiol-ene click reaction can be easily applied for copolymerizing or crosslinking the acrylate monomers for ionogels. However, there is still a problem: when the acrylate monomers contain the popular spiropyran as the stimuli-responsive group, it should be concerned about the participation of the active CC bond from the ring-opened spiropyran during a thiol-ene reaction, which may in turn affect the stimuli-responsiveness of the spiropyran. Up to now, the structure and properties of spiropyran-containing ionogels in this case have still not been well investigated. Therefore, in this work we carefully study a new spiropyran-containing polyurethane ionogel by crosslinking an acrylate-terminated, spiropyran-containing polyurethane prepolymer and a polythiol in ionic liquid through thiol-ene chemistry. It is found for the first time that, during constructing an ionogel, the coexistence of a reversible thiol-ene reaction between the CC bond from the ring-opened spiropyran and the thiol group can bring about a different reverse photochromic behavior. The proposed mechanism of the abnormal photochromism is analyzed. In addition, it is also observed that the thiol-ene chemistry can incorporate photomechanical and photoconductive properties into the new spiropyran-containing ionogel.

Rapid synthesis of functional poly(ester amide)s through thiol-ene chemistry.

Poly(ester amide)s (PEAs) bearing various side chains were synthesized by post-polymerization modification of PA-1, a vinylidene containing PEA. The thiols 1-dodecanethiol (1A-SH), 2-phenylethanethiol (1B-SH), 2-mercaptoethanol (1C-SH), thioglycolic acid (1D-SH), furfuryl mercaptan (1E-SH) and sodium-2-mercaptoethanesulfonate (1F-SH) were reacted with PA-1 to form PEAs PA-1A through PA-1F respectively. PEAs containing non-polar thiol side chains (PA-1A, PA-1B, PA-1E), showed little change in solubility compared to PA-1, while PEAs with more polar side chains improved solubility in more polar solvents. PA-1F, functionalized with sodium-2-mercaptoethanesulfonate, became water-soluble. The introduction of pendant functional groups impacted the thermal behaviors of PEAs in a wide range. The PEAs were thermally stable up to 368 °C, with glass transition temperatures (Tg) measured between 117 to 152 °C. Moreover, to demonstrate the versatility of the PEAs, thermal reprocessable networks and polyurethanes were successfully fabricated by reacting with a bismaleimide (1,6-bis(maleimido)hexane, 1,6-BMH) and a diisocyanate (4,4'-diphenylmethane diisocyanate, 4,4'-MDI), respectively. This study paves the way for the facile synthesis of functional poly(ester amide)s with great potential in many fields.

Thiyl radical induced cis/trans isomerism in double bond containing elastomers.

This report presents an evaluation of thiyl radical-induced cis/trans isomerism in double bond-containing elastomers, such as natural, polychloroprene, and polybutadiene rubbers. The study aims to extensively investigate structural changes in polymers after functionalisation using thiol-ene chemistry, a useful click reaction for modifying polymers and developing materials with new functionalities. The paper reports on the use of different thiols, and cis/trans isomerism was detected through 1H NMR analysis, even at very low alkene/thiol mole ratios. The study finds that the configurational arrangements between non-functionalised elastomer units and thiolated units followed a trans-functionalised-cis units arrangement up to an alkene/thiol mole feed ratio of 0.3, while from 0.4 onward, a combination of trans-functionalised-cis and cis-functionalised-trans configurations are found. Additionally, it is observed that by increasing the level of functionalisation, the glass transition temperature of the resulting modified elastomer also increases. Overall, this study provides valuable insights into the effects of thiol-ene chemistry on the structure and properties of elastomers and could have important implications for the development of new materials with enhanced functionality.

Matrix metalloproteinase responsive hydrogel microplates for programmed killing of invasive tumour cells.

Interactive materials are an emerging class of systems that can offer control over response and adaptivity in polymer structures towards the meso- and macroscale. Here, we use enzyme regulated cleavage of peptide crosslinkers in polymer hydrogels to release a cytotoxic therapeutic nanoparticle with an adaptable mechanism. Hydrogel microplates were formed through polyethylene glycol/peptide photoinitiated thiol-ene chemistry in a soft-lithography process to give square plates of 20 by 20 μm with a height of 10 μm. The peptide was chosen to be degradable in the presence of matrix metalloproteinase 2/9 (MMP-2/9). The hydrogel material's mechanical properties, swelling, and protease degradation were characterised. The microfabricated hydrogels were loaded with docetaxel (DTXL) containing poly(dl-lactide-co-glycolide) (PLGA) nanoparticles, and characterised for enzyme responsivity, and toxicity to MMP-2/9 overexpressing brain cancer cell line U87-MG. A 5-fold decrease in EC50 was seen compared to free DTXL, and a 20-fold decrease was seen for the MMP responsive microplates versus a non-degradable control microplate. Potential applications of this system in post-resection glioblastoma treatment are envisioned.

Vat 3D printing of full-alginate hydrogels via thiol–ene reactions towards tissue engineering applications

Different synthetic strategies are explored to functionalize alginate with thiol and alkene groups. In this way an innovative full-alginate ink for digital light processing printers, based on the more biocompatible thiol–ene chemistry, is proposed.

Functionalization of polymeric nanoparticles with targeting VNAR ligands using vinyl sulfone conjugation.

Actively targeted drug loaded nanoparticles represent an exciting new form of therapeutics for cancer and other diseases. These formulations are complex and in order to realize their ultimate potential, optimization of their preparation is required. In this current study, we have examined the conjugation of a model targeting ligand, conjugated in a site-specific manner using a vinyl sulfone coupling approach. A disulfide-functionalized poly(L-lactide)-b-poly(oligo(ethylene glycol) methacrylate)-stat-(bis(2-methacryloyl)oxyethyl disulfide) (PLA-b-P(OEGMA-stat-DSDMA)) diblock copolymer was synthesized by simultaneous ring opening polymerization (ROP) and reversible addition-fragmentation chain transfer (RAFT) polymerization. Subsequently, the disulfide bonds of the polymer were reduced to thiols and divinyl sulfone was attached to the polymer using thiol-ene chemistry to produce the vinyl sulfone (VS)-functionalized PLA-b-P(OEGMA-stat-VSTEMA) amphiphilic block copolymer. Single emulsion - solvent evaporation was employed using a blend of this polymer with poly(D,L-lactide-co-glycolide) (PLGA) to produce VS-functionalized polymeric nanoparticles. The ability of these novel nanoparticles to attach ligands was then exemplified using a single domain variable new antigen receptor (VNAR) with a free carboxyl terminal cysteine residue. The resulting VNAR-functionalized nanoparticles were found to maintain specific affinity to their cognate antigen (DLL4) for at least 72 h at 4 °C. The simplicity of the degradable amphiphilic block copolymer synthesis and the efficiency of VNAR conjugation to the VS-functionalized nanoparticles show the potential of this platform for therapeutic development.

Bioinspired polydopamine-mediated metal-organic framework click-grafting aptamers functionalized fabric for highly-specific recognition of microcystin-leucine arginine

Fabricating functional electrospun nanofiber coating for highly selective extraction of microcystin-LR (MC-LR) was of significant importance for water-safety monitoring. Herein, a novel MOF@aptamer functionalized nanofabric was presented via a facile and reliable strategy integrating polydopamine (PDA) mediation and thiol-ene chemistry and applied for specific recognition of the MC-LR model analyte. Using polydopamine (PDA) as the mediating layer, vinyl-UiO-66 MOF was grown in situ, followed by post-synthetic modification (PSM) of Zr4+ with vinyl phosphate and rapid UV-initiated click reaction of aptamers. Uniform deposition of Zr-based MOF (vinyl-UiO-66) on the nanofibers was directly produced, and the tedious co-electrospinning process was abandoned to prevent the aggregation and encapsulation of MOF. Via an efficient “thiol-ene” chemistry, massive thiol-terminated aptamers were grafted on MOF within one step under friendly conditions, rather than the time-consuming nanoparticle adsorption or unfriendly covalent chemical reactions. As a result, the robust MOF@aptamer-coated nano-fabrics were obtained, and a highly selective performance towards MC-LR was illustrated with a limit of detection (LOD) at 0.002 ng/mL, good precision (CV<8.3%), good repeatability (2.2∼6.0%) when coupled with LC-MS. Almost 1∼2 orders of magnitude higher detection sensitivity was exhibited than that of the common non-specific SPE/SPME fiber reported so far. Applied to water samples, the good matrix-resistance ability, and acceptable recovery yields were achieved with high specificity. This strategy might provide a rapid and friendly protocol to efficiently fabricate MOF@aptamer functionalized nano-fabrics through electrospinning and interfacial "thiol-ene" chemistry for highly-selective microextraction.

Concentration Dependent Effect of Quaternary Amines on the Adhesion of U251-MG Cells.

Cationic gels have seen increasing interest in recent years for 2D cell cultivation since they may represent an alternative to the well-known RGD-peptide motif functionalized gels. However, few hydrogel systems with adjustable cationic strength have been fabricated and investigated so far. In this work, eight gels with defined concentrations of cationic groups, two of which also contained the RGD peptide, were prepared from three well-defined, soluble precursor copolymers with thiol-functionalities and PEGDA3500 as a crosslinker via thiol-ene chemistry. Live/dead stainings of U-251-MG cells on the hydrogels with different concentrations of the cationic motif were made after 3 days and 7 days of cultivation. The results show a high dependence of the number of adhesive cells and their morphology, cluster versus spread cells, on the concentration of cationic groups in the gel. This effect was more pronounced when the gels were not further dialyzed before usage. In addition, a synergistic effect of the two motifs, cationic group and RGD peptide, could be demonstrated, which together induce stronger cell adhesion than either motif alone.

Synthesis, Characterization, and Digital Light Processing of a Hydrolytically Degradable Hyaluronic Acid Hydrogel.

Numerous chemical modifications of hyaluronic acid (HA) have been explored for the formation of degradable hydrogels that are suitable for a variety of biomedical applications, including biofabrication and drug delivery. Thiol-ene step-growth chemistry is of particular interest due to its lower oxygen sensitivity and ability to precisely tune mechanical properties. Here, we utilize an aqueous esterification route via reaction with carbic anhydride to synthesize norbornene-modified HA (NorHACA) that is amenable to thiol-ene crosslinking to form hydrolytically unstable networks. NorHACA is first synthesized with varying degrees of modification (∼15-100%) by adjusting the ratio of reactive carbic anhydride to HA. Thereafter, NorHACA is reacted with dithiol crosslinker in the presence of visible light and photoinitiator to form hydrogels within tens of seconds. Unlike conventional NorHA, NorHACA hydrogels are highly susceptible to hydrolytic degradation through enhanced ester hydrolysis. Both the mechanical properties and the degradation timescales of NorHACA hydrogels are tuned via macromer concentration and/or the degree of modification. Moreover, the degradation behavior of NorHACA hydrogels is validated through a statistical-co-kinetic model of ester hydrolysis. The rapid degradation of NorHACA hydrogels can be adjusted by incorporating small amounts of slowly degrading NorHA macromer into the network. Further, NorHACA hydrogels are implemented as digital light processing (DLP) resins to fabricate hydrolytically degradable scaffolds with complex, macroporous structures that can incorporate cell-adhesive sites for cell attachment and proliferation after fabrication. Additionally, DLP bioprinting of NorHACA hydrogels to form cell-laden constructs with high viability is demonstrated, making them useful for applications in tissue engineering and regenerative medicine.

Aptamer-Based Gold Nanoparticles-PDMS Composite Stamps as a Platform for Micro-Contact Printing.

In the present study, a functional template made up of in situ synthesised gold nanoparticles (AuNPs) is prepared on polydimethylsiloxane (PDMS) for patterning of target protein onto the desired solid substrates. Unlike previous studies in which bioreceptor probes are randomly attached to the PDMS stamp through electrostatic interactions, herein, we propose an AuNPs-PDMS stamp, which provides a surface for the attachment of thiol-modified biorecognition probes to link to the stamp surface through a dative bond with a single anchoring point based on thiol chemistry. By using this platform, we have developed the ability for microcontact printing (µCP) to selectively capture and transfer target protein onto solid surfaces for detection purposes. After µCP, we also investigated whether liquid crystals (LCs) could be used as a label-free approach for identifying transfer protein. Our reported approach provides promise for biosensing of various analytes.

Synthesis, Antibacterial Activity, and Nephrotoxicity of Polymyxin B Analogues Modified at Leu-7, d-Phe-6, and the N-Terminus Enabled by S-Lipidation.

With the post-antibiotic era rapidly approaching, many have turned their attention to developing new treatments, often by structural modification of existing antibiotics. Polymyxins, a family of lipopeptide antibiotics that are used as a last line of defense in the clinic, have recently developed resistance and exhibit significant nephrotoxicity issues. Using thiol-ene chemistry, the facile preparation of six unique S-lipidated building blocks was demonstrated and used to generate lipopeptide mimetics upon incorporation into solid-phase peptide synthesis (SPPS). We then designed and synthesized 38 polymyxin analogues, incorporating these unique building blocks at the N-terminus, or to replace hydrophobic residues at positions 6 and 7 of the native lipopeptides. Several polymyxin analogues bearing one or more S-linked lipids were found to be equipotent to polymyxin, showed minimal kidney nephrotoxicity, and demonstrated activity against several World Health Organisation (WHO) priority pathogens. The S-lipidation strategy has demonstrated potential as a novel approach to prepare innovative new lipopeptide antibiotics.