Solution Conditions Tune and Optimize Loading of Therapeutic Polyelectrolytes into Layer-by-Layer Functionalized Liposomes

Development of novel lipoplex formulation methodologies to improve large-scale transient transfection for lentiviral vector manufacture

Large-scale transient transfection has advanced significantly over the last 20 years, enabling the effective production of a diverse range of biopharmaceutical products, including viral vectors. However, a number of challenges specifically related to transfection reagent stability and transfection complex preparation times remain. New developments and improved transfection technologies are required to ensure that transient gene expression-based bioprocesses can meet the growing demand for viral vectors. In this paper, we demonstrate that the growth of cationic lipid-based liposomes, an essential step in many cationic lipid-based transfection processes, can be controlled through adoption of low pH (pH 6.40 to pH 6.75) and in low salt concentration (0.2× PBS) formulations, facilitating improved control over the nanoparticle growth kinetics and enhancing particle stability. Such complexes retain the ability to facilitate efficient transfection for prolonged periods compared with standard preparation methodologies. These findings have significant industrial applications for the large-scale manufacture of lentiviral vectors for two principal reasons. First, the alternative preparation strategy enables longer liposome incubation times to be used, facilitating effective control in a good manufacturing practices setting. Second, the improvement in particle stability facilitates the setting of wider process operating ranges, which will significantly improve process robustness and maximise batch-to-batch control and product consistency.

Carboxylated Nanoparticle Surfaces Enhance Association with Mucoid Pseudomonas aeruginosa Biofilms

Pseudomonas aeruginosa biofilms comprise three main polysaccharides: alginate, psl, and pel, which all imbue tolerance against exogenous antimicrobials. Nanoparticles (NPs) are an exciting new strategy to overcome the biofilm matrix for therapeutic delivery applications; however, zero existing FDA approvals for biofilm-specific NP formulations can be attributed to the complex interplay of physiochemical forces at the biofilm-NP interface. Here, we leverage a set of inducible, polysaccharide-specific, expressing isogenic P. aeruginosa mutants coupled with an assembled layer-by-layer NP (LbL NP) panel to characterize biofilm-NP interactions. When investigating these interactions using confocal microscopy, alginate-layered NPs associated more than dextran-sulfate-layered NPs with biofilms that had increased alginate production, including biofilms produced by mucoid P. aeruginosa isolates from people with cystic fibrosis. These differences were further confirmed in LbL NPs layered with polysaccharide- or hydrocarbon-based polymers with pendent carboxylate or sulfate functional groups. These data suggest carboxylated NP surfaces have enhanced interactions specifically with mucoid biofilms as compared to sulfated surfaces and lay the foundation for their inclusion as a design element for increasing biofilm-NP interactions and efficacious drug delivery.

Electrostatic adsorption of polyanions onto lipid nanoparticles controls uptake, trafficking, and transfection of RNA and DNA therapies

Rapid advances in nucleic acid therapies highlight the immense therapeutic potential of genetic therapeutics. Lipid nanoparticles (LNPs) are highly potent nonviral transfection agents that can encapsulate and deliver various nucleic acid therapeutics, including but not limited to messenger RNA (mRNA), silencing RNA (siRNA), and plasmid DNA (pDNA). However, a major challenge of targeted LNP-mediated systemic delivery is the nanoparticles' nonspecific uptake by the liver and the mononuclear phagocytic system, due partly to the adsorption of endogenous serum proteins onto LNP surfaces. Tunable LNP surface chemistries may enable efficacious delivery across a range of organs and cell types. Here, we describe a method to electrostatically adsorb bioactive polyelectrolytes onto LNPs to create layered LNPs (LLNPs). LNP cores varying in nucleic acid cargo and component lipids were stably layered with four biologically relevant polyanions: hyaluronate (HA), poly-L-aspartate (PLD), poly-L-glutamate (PLE), and polyacrylate (PAA). We further investigated the impact of the four surface polyanions on the transfection and uptake of mRNA- and pDNA-loaded LNPs in cell cultures. PLD- and PLE-LLNPs increased mRNA transfection twofold over unlayered LNPs in immune cells. HA-LLNPs increased pDNA transfection rates by more than twofold in epithelial and immune cells. In a healthy C57BL/6 murine model, PLE- and HA-LLNPs increased transfection by 1.8-fold to 2.5-fold over unlayered LNPs in the liver and spleen. These results suggest that LbL assembly is a generalizable, highly tunable platform to modify the targeting specificity, stability, and transfection efficacy of LNPs, as well as incorporate other charged targeting and therapeutic molecules into these systems.

Nanotechnology in development of next generation of stent and related medical devices: Current and future aspects

Coronary stents have saved millions of lives in the last three decades by treating atherosclerosis especially, by preventing plaque protrusion and subsequent aneurysms. They attenuate the vascular SMC proliferation and promote reconstruction of the endothelial bed to ensure superior revascularization. With the evolution of modern stent types, nanotechnology has become an integral part of stent technology. Nanocoating and nanosurface fabrication on metallic and polymeric stents have improved their drug loading capacity as well as other mechanical, physico-chemical, and biological properties. Nanofeatures can mimic the natural nanofeatures of vascular tissue and control drug-delivery. This review will highlight the role of nanotechnology in addressing the challenges of coronary stents and the recent advancements in the field of related medical devices. Different generations of stents carrying nanoparticle-based formulations like liposomes, lipid-polymer hybrid NPs, polymeric micelles, and dendrimers are discussed highlighting their roles in local drug delivery and anti-restenotic properties. Drug nanoparticles like Paclitaxel embedded in metal stents are discussed as a feature of first-generation drug-eluting stents. Customized precision stents ensure safe delivery of nanoparticle-mediated genes or concerted transfer of gene, drug, and/or bioactive molecules like antibodies, gene mimics via nanofabricated stents. Nanotechnology can aid such therapies for drug delivery successfully due to its easy scale-up possibilities. However, limitations of this technology such as their potential cytotoxic effects associated with nanoparticle delivery that can trigger hypersensitivity reactions have also been discussed in this review. This article is categorized under: Implantable Materials and Surgical Technologies > Nanotechnology in Tissue Repair and Replacement Therapeutic Approaches and Drug Discovery > Nanomedicine for Cardiovascular Disease Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Layer-by-layer designer nanoarchitectonics for physical and chemical communications in functional materials

Nanoarchitectonics, as a post-nanotechnology concept, constructs functional materials and structures using nanounits of atoms, molecules, and nanomaterials as materials. With the concept of nanoarchitectonics, asymmetric structures, and hierarchical organization, rather than mere assembly and organization of structures, can be produced, where rational physical and chemical communications will lead to the development of more advanced functional materials. Layer-by-layer assembly can be a powerful tool for this purpose, as exemplified in this feature paper. This feature article explores the possibility of constructing advanced functional systems based on recent examples of layer-by-layer assembly. We will illustrate both the development of more basic methods and more advanced nanoarchitectonics systems aiming towards practical applications. Specifically, the following sections will provide examples of (i) advancement in basics and methods, (ii) physico-chemical aspects and applications, (iii) bio-chemical aspects and applications, and (iv) bio-medical applications. It can be concluded that materials nanoarchitectonics based on layer-by-layer assembly is a useful method for assembling asymmetric structures and hierarchical organization, and is a powerful technique for developing functions through physical and chemical communication.

Preparation and Characterization of Novel Polyelectrolyte Liposomes Using Chitosan Succinate Layered over Chitosomes: A Potential Strategy for Colon Cancer Treatment

Chitosan succinate is distinguished by its ability to shield the loaded drug from the acidic environment, localize and keep the drug at the colon site, and release the drug over an extended time at basic pH. The current study attempts to develop polyelectrolyte liposomes (PEL), using chitosan and chitosan succinate (CSSC), as a carrier for liposomal-assisted colon target delivery of 5 fluorouracil (5FU). The central composite design was used to obtain an optimized formulation of 5FU-chitosomes. The chitosan-coated liposomes (chitosomes) were prepared by thin lipid film hydration technique. After that, the optimized formulation was coated with CSSC, which has several carboxylic (COOH) groups that produce an anionic charge that interacts with the cation NH2 in chitosan. The prepared 5FU-chitosomes formulations were evaluated for entrapment efficiency % (EE%), particle size, and in vitro drug release. The optimized 5FU-chitosomes formulation was examined for particle size, zeta potential, in vitro release, and mucoadhesive properties in comparison with the equivalent 5FU-liposomes and 5FU-PEL. The prepared 5FU-chitosomes exhibited high EE%, small particle size, low polydispersity index, and prolonged drug release. PEL significantly limited the drug release at acidic pH due to the deprotonation of carboxylate ions in CSSC, which resulted in strong repulsive forces, significant swelling, and prolonged drug release. According to a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay, PEL treatment significantly decreased the viability of HT-29 cells. When compared to 5FU-liposome and 5FU-chitosome, the in vivo pharmacokinetics characteristics of 5FU-PEL significantly (p < 0.05) improved. The findings show that PEL enhances 5FU permeability, which permits high drug concentrations to enter cells and inhibits the growth of colon cancer cells. Based on the current research, PEL may be used as a liposomal-assisted colon-specific delivery.

Chondroitin sulfate and chitosan-coated liposomes as a novel delivery system for betanin: Preparation, characterization and in vitro digestion behavior

Betanin, a water-soluble pigment known for its high bioactivity, is hindered by pH and temperature sensitivity, weak ionic strength, and low bioavailability. In this study, nanoliposome (NPS), chitosan-coated NPS (CNPS), and chondroitin sulfate-chitosan bilayer-modified nanoliposomes (SCNPS) were prepared based on a layer-by-layer electrostatic interaction method for betanin encapsulation. The increase of polymer layers from NPS to SCNPS led to a monotonic increment from 223.57 to 522.33 nm in size, from -27.73 to 16.70 mV in negative charge and from 0.22 to 0.35 in polydispersity index. The chemical stability against pH (ranging from 2 to 10), ionic type (KCl, CaCl2, ALCl3) and ionic strength (100, 500 mM) significantly impacted the appearance and particle size of the double-layered nanoliposome. In vitro digestion experiment showed that SCNPS displayed higher stability and slower betanin release compared to NPS and CNPS. This study demonstrates that betanin can be efficiently encapsulated by SCNPS with improved stability and bioavailability.

Layer-by-Layer Polymer Functionalization Improves Nanoparticle Penetration and Glioblastoma Targeting in the Brain

Glioblastoma is characterized by diffuse infiltration into surrounding healthy brain tissues, which makes it challenging to treat. Complete surgical resection is often impossible, and systemically delivered drugs cannot achieve adequate tumor exposure to prevent local recurrence. Convection-enhanced delivery (CED) offers a method for administering therapeutics directly into brain tumor tissue, but its impact has been limited by rapid clearance and off-target cellular uptake. Nanoparticle (NP) encapsulation presents a promising strategy for extending the retention time of locally delivered therapies while specifically targeting glioblastoma cells. However, the brain's extracellular structure poses challenges for NP distribution due to its narrow, tortuous pores and a harsh ionic environment. In this study, we investigated the impact of NP surface chemistry using layer-by-layer (LbL) assembly to design drug carriers for broad spatial distribution in brain tissue and specific glioblastoma cell targeting. We found that poly-l-glutamate and hyaluronate were effective surface chemistries for targeting glioblastoma cells in vitro. Coadsorbing either polymer with a small fraction of PEGylated polyelectrolytes improved the colloidal stability without sacrificing cancer cell selectivity. Following CED in vivo, gadolinium-functionalized LbL NPs enabled MRI visualization and exhibited a distribution volume up to three times larger than liposomes and doubled the retention half-time up to 13.5 days. Flow cytometric analysis of CED-treated murine orthotopic brain tumors indicated greater cancer cell uptake and reduced healthy cell uptake for LbL NPs compared to nonfunctionalized liposomes. The distinct cellular outcomes for different colayered LbL NPs provide opportunities to tailor this modular delivery system for various therapeutic applications.

Multifunctional mesoporous silica nanoparticles for biomedical applications

Mesoporous silica nanoparticles (MSNs) are recognized as a prime example of nanotechnology applied in the biomedical field, due to their easily tunable structure and composition, diverse surface functionalization properties, and excellent biocompatibility. Over the past two decades, researchers have developed a wide variety of MSNs-based nanoplatforms through careful design and controlled preparation techniques, demonstrating their adaptability to various biomedical application scenarios. With the continuous breakthroughs of MSNs in the fields of biosensing, disease diagnosis and treatment, tissue engineering, etc., MSNs are gradually moving from basic research to clinical trials. In this review, we provide a detailed summary of MSNs in the biomedical field, beginning with a comprehensive overview of their development history. We then discuss the types of MSNs-based nanostructured architectures, as well as the classification of MSNs-based nanocomposites according to the elements existed in various inorganic functional components. Subsequently, we summarize the primary purposes of surface-functionalized modifications of MSNs. In the following, we discuss the biomedical applications of MSNs, and highlight the MSNs-based targeted therapeutic modalities currently developed. Given the importance of clinical translation, we also summarize the progress of MSNs in clinical trials. Finally, we take a perspective on the future direction and remaining challenges of MSNs in the biomedical field.

pH-Responsive, Charge-Reversing Layer-by-Layer Nanoparticle Surfaces Enhance Biofilm Penetration and Eradication

Microbes entrenched within biofilms can withstand 1000-fold higher concentrations of antibiotics, in part due to the viscous extracellular matrix that sequesters and attenuates antimicrobial activity. Nanoparticle (NP)-based therapeutics can aid in delivering higher local concentrations throughout biofilms as compared to free drugs alone, thereby enhancing the efficacy. Canonical design criteria dictate that positively charged nanoparticles can multivalently bind to anionic biofilm components and increase biofilm penetration. However, cationic particles are toxic and are rapidly cleared from circulation in vivo, limiting their use. Therefore, we sought to design pH-responsive NPs that change their surface charge from negative to positive in response to the reduced biofilm pH microenvironment. We synthesized a family of pH-dependent, hydrolyzable polymers and employed the layer-by-layer (LbL) electrostatic assembly method to fabricate biocompatible NPs with these polymers as the outermost surface. The NP charge conversion rate, dictated by polymer hydrophilicity and the side-chain structure, ranged from hours to undetectable within the experimental timeframe. LbL NPs with an increasingly fast charge conversion rate more effectively penetrated through, and accumulated throughout, wildtype (PAO1) and mutant overexpressing biomass (ΔwspF) Pseudomonas aeruginosa biofilms. Finally, tobramycin, an antibiotic known to be trapped by anionic biofilm components, was loaded into the final layer of the LbL NP. There was a 3.2-fold reduction in ΔwspF colony forming units for the fastest charge-converting NP as compared to both the slowest charge converter and free tobramycin. These studies provide a framework for the design of biofilm-penetrating NPs that respond to matrix interactions, ultimately increasing the efficacious delivery of antimicrobials.

A Molecular Thermodynamic Model of Coacervation in Solutions of Polycations and Oppositely Charged Micelles

To guide the rational design of personal care formulations, we formulate a molecular thermodynamic model that predicts coacervation from cationic polymers and mixed micelles containing neutral and anionic surfactants and added salt. These coacervates, which form as a result of dilution of conditioning shampoos during use, deposit conditioning agents and other actives to the scalp or skin and also provide lubrication benefits. Our model accounts for mixing entropy, hydrophobic interactions of polycation with water, free energies of bindings of oppositely charged groups to micelles and polycations, and electrostatic interactions that capture connectivity of charged groups on the polycation chain and the micelle. The model outputs are the compositions of surfactants, polycation, salt, and water in the coacervate and in its coexisting dilute phase, along with the binding fractions and coacervate volume fraction. We study the effects of overall composition (of surfactant, polycation, and added salt), charge fractions on micelles and polycations, and binding free energies on the phase diagram of coacervates. Then, we perform coacervation experiments for three systems: sodium dodecyl sulfate (SDS)-JR30M, sodium methyl cocoyl taurate (Taurate)-JR30M, and sodium lauryl alaninate (Alaninate)-JR30M, where JR30M is a cationic derivative of hydroxyethylcellulose (cat-HEC), and rationalize their coacervation data using our model. For comparison with experiment, we also develop a parametrization scheme to obtain the requisite binding energies and Flory-Huggins χ parameter. We find that our model predictions agree reasonably well with the experimental data, and that the sulfate-free surfactants of Taurate and Alaninate display much larger 2-phase regions compared to SDS with JR30M.

Tailoring the Inherent Properties of Biobased Nanoparticles for Nanomedicine

Biobased nanoparticles are at the leading edge of the rapidly developing field of nanomedicine and biotherapeutics. Their unique size, shape, and biophysical properties make them attractive tools for biomedical research, including vaccination, targeted drug delivery, and immune therapy. These nanoparticles are engineered to present native cell receptors and proteins on their surfaces, providing a biomimicking camouflage for therapeutic cargo to evade rapid degradation, immune rejection, inflammation, and clearance. Despite showing promising clinical relevance, commercial implementation of these biobased nanoparticles is yet to be fully realized. In this perspective, we discuss advanced biobased nanoparticle designs used in medical applications, such as cell membrane nanoparticles, exosomes, and synthetic lipid-derived nanoparticles, and highlight their benefits and potential challenges. Moreover, we critically assess the future of preparing such particles using artificial intelligence and machine learning. These advanced computational tools will be able to predict the functional composition and behavior of the proteins and cell receptors present on the nanoparticle surfaces. With more advancement in designing new biobased nanoparticles, this field of research could play a key role in dictating the future rational design of drug transporters, thereby ultimately improving overall therapeutic outcomes.

Synergistic combination therapy delivered via layer-by-layer nanoparticles induces solid tumor regression of ovarian cancer

The majority of patients with high grade serous ovarian cancer (HGSOC) develop recurrent disease and chemotherapy resistance. To identify drug combinations that would be effective in treatment of chemotherapy resistant disease, we examined the efficacy of drug combinations that target the three antiapoptotic proteins most commonly expressed in HGSOC-BCL2, BCL-XL, and MCL1. Co-inhibition of BCL2 and BCL-XL (ABT-263) with inhibition of MCL1 (S63845) induces potent synergistic cytotoxicity in multiple HGSOC models. Since this drug combination is predicted to be toxic to patients due to the known clinical morbidities of each drug, we developed layer-by-layer nanoparticles (LbL NPs) that co-encapsulate these inhibitors in order to target HGSOC tumor cells and reduce systemic toxicities. We show that the LbL NPs can be designed to have high association with specific ovarian tumor cell types targeted in these studies, thus enabling a more selective uptake when delivered via intraperitoneal injection. Treatment with these LbL NPs displayed better potency than free drugs in vitro and resulted in near-complete elimination of solid tumor metastases of ovarian cancer xenografts. Thus, these results support the exploration of LbL NPs as a strategy to deliver potent drug combinations to recurrent HGSOC. While these findings are described for co-encapsulation of a BCL2/XL and a MCL1 inhibitor, the modular nature of LbL assembly provides flexibility in the range of therapies that can be incorporated, making LbL NPs an adaptable vehicle for delivery of additional combinations of pathway inhibitors and other oncology drugs.

A decade of developing applications exploiting the properties of polyelectrolyte multilayer capsules

Transferring the layer-by-layer (LbL) coating approach from planar surfaces to spherical templates and subsequently dissolving these templates leads to the fabrication of polyelectrolyte multilayer capsules. The versatility of the coatings of capsules and their flexibility upon bringing in virtually any material into the coatings has quickly drawn substantial attention. Here, we provide an overview of the main developments in this field, highlighting the trends in the last decade. In the beginning, various methods of encapsulation and release are discussed followed by a broad range of applications, which were developed and explored. We also outline the current trends, where the range of applications is continuing to grow, including addition of whole new and different application areas.

Surface Presentation of Hyaluronic Acid Modulates Nanoparticle-Cell Association

Nanoparticle (NP) drug carriers have revolutionized medicine and increased patient quality of life. Clinically approved formulations typically succeed because of reduced off-target toxicity of the cargo. However, increasing carrier accumulation at disease sites through precise targeting remains one of the biggest challenges in the field. Novel multivalent ligand presentations and self-assembled constructs can enhance cell association, but an inability to draw direct comparisons across formulations has hindered progress. Furthermore, how nanoparticle structure influences function often is unclear. In this report, we leverage the well-characterized hyaluronic acid (HA)-CD44 binding pair to investigate how the surface architecture of modified NPs impacts their association with ovarian cancer cells that overexpress CD44. We functionalized anionic liposomes with 5 kDa HA by either covalent conjugation via surface coupling or electrostatic self-assembly using the layer-by-layer (LbL) adsorption method. Comparing these two methods, we observed a consistent enhancement of NP-cell association with the self-assembly LbL technique, particularly with higher molecular weight (≥10 kDa) HA. To further optimize association, we increased the surface-available HA. We synthesized a bottlebrush glycopolymer composed of a polynorbornene backbone and pendant 5 kDa HA and layered this macromolecule onto NPs. Flow cytometry revealed that the LbL HA bottlebrush NP outperformed the LbL linear display of HA. Cellular visualization by deconvolution optical microscopy corroborated results from all three constructs. Using exogenous HA to block NP-CD44 interactions, we found the LbL HA bottlebrush NP had a 4-fold higher binding avidity than the best-performing LbL linear HA NP. We further observed that decreasing the density of HA bottlebrush side chains to 75% had minimal impact on LbL NP stability or cell association, though we did see a reduction in binding avidity with this side-chain-modified NP. Our studies indicate that LbL surfaces are highly effective for multivalent displays, and the mode in which they present a targeting ligand can be optimized for NP cell targeting.

Nanoarchitectonics beyond perfect order - not quite perfect but quite useful

Nanoarchitectonics, like architectonics, allows the design and building of structures, but at the nanoscale. Unlike those in architectonics, and even macro-, micro-, and atomic-scale architectonics, the assembled structures at the nanoscale do not always follow the projected design. In fact, they do follow the projected design but only for self-assembly processes producing structures with perfect order. Here, we look at nanoarchitectonics allowing the building of nanostructures without a perfect arrangement of building blocks. Here, fabrication of structures from molecules, polymers, nanoparticles, and nanosheets to polymer brushes, layer-by-layer assembly structures, and hydrogels through self-assembly processes is discussed, where perfect order is not necessarily the aim to be achieved. Both planar substrate and spherical template-based assemblies are discussed, showing the challenging nature of research in this field and the usefulness of such structures for numerous applications, which are also discussed here.

pH-Responsive Drug Delivery and Imaging Study of Hybrid Mesoporous Silica Nanoparticles

A system of pH-responsive and imaging nanocarriers was developed using mesoporous silica nanoparticles (MSNs), in which gadolinium (Gd) was doped through in situ doping (Gd₂O₃@MSN). Sodium alginate (SA) was attached to the surfaces of the amino groups of MSNs (NH₂-Gd₂O₃@MSN) through the electrostatic adsorption between the amino groups and the carboxyl groups with the formation of hybrid SA-Gd₂O₃@MSN nanoparticles (NPs). The SA-coated NPs were spherical or near-spherical in shape with an average size of nearly 83.2 ± 8.7 nm. The in vitro drug release experiments of a model rhodamine B (RhB) cargo were performed at different pH values. The result confirmed the pH-responsiveness of the nanocarriers. The results of the cytotoxicity studies indicated that the SA-Gd₂O₃@MSN NPs were not cytotoxic by themselves. The results of the in vivo safety evaluation and the hemolysis assay confirmed that the system is highly biocompatible. It is noteworthy that the T1 contrast of the system was significantly enhanced by the Gd, as indicated by the result of the MR imaging. This study confirms that the synthesized hybrid nanosystem is promising for pH-responsive drug delivery and MR imaging for cancer diagnosis and treatment.

Layer-by-layer self-assembled emerging systems for nanosized drug delivery

New frontiers in the development of stimuli-responsive surfaces that offer switchable properties according to the end-use application have added a new dimension to the design of drug-delivery systems (DDS). In this respect, layer-by-layer (LbL) self-assembled technologies have attracted interest in nano-DDS (NDDS) design due to the advantage of encapsulating different drug types either individually or in multiple formulations as an easy-to-apply and cost-effective strategy. LbL-based microcapsules and core-shell structures in the form of polyelectrolyte multilayers (PEMs) have been proposed as versatile vehicles for NDDS over the last quarter. This review aims to provide a global view of LbL-PEMs used as templates in NDDS for the last 5 years with an emphasis on emerging drug loading and release strategies.

Quality-by-design-based engineered liposomal nanomedicines to treat cancer: an in-depth analysis

Engineered nano-sized liposomes have attained the highest success rate in commercialization among the reported nanomedicines. However, developing industrially acceptable nanoliposomes is still challenging because the process, formulation factors and even their properties may critically influence the desired attributes of the final nanoliposomal product. Implementation of quality-by-design (QbD) in nanoliposomal fabrication has led to revolutionary advancement int better analysis of the interacting factors (drug and lipid ratio, hydration, sonication, etc), which, in turn, leads to better product performance with predefined attributes (entrapment efficiency percentage, drug release time and pattern, vesicles size, polydispersity index, surface charge and surface morphology). This review provides a summary of decade of research and an in-depth analysis of QbD-based nanoliposomes developed to address different cancers. The review aims to provide complete details of QbD-inspired nanoliposomal development from process to application.

pH-Responsive Polyelectrolyte Coatings that Enable Catheter-Mediated Transfer of DNA to the Arterial Wall in Short and Clinically Relevant Inflation Times

We report the design and characterization of pH-responsive polymer coatings that enable catheter balloon-mediated transfer of DNA to arterial tissue in short, clinically relevant inflation times. Our approach exploits the pH-dependent ionization of poly(acrylic acid) (PAA) to promote disassembly and release of plasmid DNA from polyelectrolyte multilayers. We characterized the contact transfer of multilayers composed of PAA, plasmid DNA, and linear poly(ethyleneimine) (LPEI) identified as promising in prior studies on the delivery of DNA to arterial tissue. In contrast to thinner films evaluated previously, we found thicker coatings composed of 32 repeating (LPEI/PAA/LPEI/DNA)_x tetralayers to swell substantially in physiologically relevant media (in PBS; pH = 7.4). In some cases, these coatings also disintegrated or delaminated rapidly from their underlying substrates, suggesting the potential for enhanced balloon-mediated transfer. We developed a technically straightforward agarose gel-based hole-insertion model to characterize factors (inflation time, lumen size, etc.) that influence contact transfer of DNA when film-coated balloons are inflated into contact with soft surfaces. Those studies and the results of in vivo experiments using small animal (rat) and large animal (pig) models of peripheral arterial injury revealed catheters coated with these materials to promote robust contact transfer of DNA to soft hydrogel surfaces and the luminal surfaces of arterial tissue using inflation times as short as 30 s. These short inflation times are relevant in the context of clinical vascular interventions in peripheral arteries. Additional studies demonstrated that contact transfer of DNA using these short times can promote subsequent dissemination and transport of DNA to the medial tissue layer, suggesting the potential for use in therapeutically relevant applications of balloon-mediated gene transfer.

Massively parallel pooled screening reveals genomic determinants of nanoparticle delivery

To accelerate the translation of cancer nanomedicine, we used an integrated genomic approach to improve our understanding of the cellular processes that govern nanoparticle trafficking. We developed a massively parallel screen that leverages barcoded, pooled cancer cell lines annotated with multiomic data to investigate cell association patterns across a nanoparticle library spanning a range of formulations with clinical potential. We identified both materials properties and cell-intrinsic features that mediate nanoparticle-cell association. Using machine learning algorithms, we constructed genomic nanoparticle trafficking networks and identified nanoparticle-specific biomarkers. We validated one such biomarker: gene expression of SLC46A3, which inversely predicts lipid-based nanoparticle uptake in vitro and in vivo. Our work establishes the power of integrated screens for nanoparticle delivery and enables the identification and utilization of biomarkers to rationally design nanoformulations.

Exploiting the layer-by-layer nanoarchitectonics for the fabrication of polymer capsules: A toolbox to provide multifunctional properties to target complex pathologies

Polymer capsules fabricated via the layer-by-layer (LbL) approach have attracted a great deal of attention for biomedical applications thanks to their tunable architecture. Compared to alternative methods, in which the precise control over the final properties of the systems is usually limited, the intrinsic versatility of the LbL approach allows the functionalization of all the constituents of the polymeric capsules following relatively simple protocols. In fact, the final properties of the capsules can be adjusted from the inner cavity to the outer layer through the polymeric shell, resulting in therapeutic, diagnostic, or theranostic (i.e., combination of therapeutic and diagnostic) agents that can be adapted to the particular characteristics of the patient and face the challenges encountered in complex pathologies. The biomedical industry demands novel biomaterials capable of targeting several mechanisms and/or cellular pathways simultaneously while being tracked by minimally invasive techniques, thus highlighting the need to shift from monofunctional to multifunctional polymer capsules. In the present review, those strategies that permit the advanced functionalization of polymer capsules are accordingly introduced. Each of the constituents of the capsule (i.e., cavity, multilayer membrane and outer layer) is thoroughly analyzed and a final overview of the combination of all the strategies toward the fabrication of multifunctional capsules is presented. Special emphasis is given to the potential biomedical applications of these multifunctional capsules, including particular examples of the performed in vitro and in vivo validation studies. Finally, the challenges in the fabrication process and the future perspective for their safe translation into the clinic are summarized.

Polymer-Modified Liposomes for Drug Delivery: From Fundamentals to Applications

Liposomes are highly advantageous platforms for drug delivery. To improve the colloidal stability and avoid rapid uptake by the mononuclear phagocytic system of conventional liposomes while controlling the release of encapsulated agents, modification of liposomes with well-designed polymers to modulate the physiological, particularly the interfacial properties of the drug carriers, has been intensively investigated. Briefly, polymers are incorporated into liposomes mainly using “grafting” or “coating”, defined according to the configuration of polymers at the surface. Polymer-modified liposomes preserve the advantages of liposomes as drug-delivery carriers and possess specific functionality from the polymers, such as long circulation, precise targeting, and stimulus-responsiveness, thereby resulting in improved pharmacokinetics, biodistribution, toxicity, and therapeutic efficacy. In this review, we summarize the progress in polymer-modified liposomes for drug delivery, focusing on the change in physiological properties of liposomes and factors influencing the overall therapeutic efficacy.

A design approach for layer-by-layer surface-mediated siRNA delivery

The ability to coat scaffolds and wound dressings with therapeutic short interfering RNA (siRNA) holds much potential for applications in wound healing, cancer treatment, and regenerative medicine. Layer-by-layer (LbL) technology is an effective method to formulate polyelectrolyte thin films for local delivery of siRNA; however, the formation and efficacy of LbL coatings as drug delivery systems are highly contingent on the assembly conditions. Here, we investigate the effects of LbL assembly parameters on film composition and consequent siRNA-mediated gene knockdown efficiency in vitro. Films comprising poly(β-amino ester) (PBAE) and siRNA were built on polyglactin 910 (Vicryl) sutures consisting of poly(10% L-lactide, 90% glycolide). A fractional factorial design was employed, varying the following LbL assembly conditions: pH, ionic strength, PBAE concentration, and siRNA concentration. Effects of these parameters on PBAE loading, siRNA loading, their respective weight ratios, and in vitro siRNA-mediated knockdown were elucidated. The parameter effects were leveraged to create a rationally designed set of solution conditions that was predicted to give effective siRNA-mediated knockdown, but not included in any of the original experimental conditions. This level of knockdown with our rationally designed loading conditions (47%) is comparable to previous formulations from our lab while being simpler in construction and requiring fewer film layers, which could save time and cost in manufacturing. This study highlights the importance of LbL solution conditions in the preparation of surface-mediated siRNA delivery systems and presents an adaptable methodology for extending these electrostatically-assembled coatings to the delivery of other therapeutic nucleic acids. STATEMENT OF SIGNIFICANCE: Short interfering RNA (siRNA) therapeutics are powerful tools to silence aberrant gene expression in the diseased state; however, the clinical utility of these therapies relies on effective controlled delivery approaches. Electrostatic self-assembly through the layer-by-layer (LbL) process enables direct siRNA release from surfaces, but this method is highly dependent upon the specific solution conditions used. Here, we use a fractional factorial design to illustrate how these assembly conditions impact composition of siRNA-eluting LbL thin films. We then elucidate how these properties mediate in vitro transfection efficacy. Ultimately, this work presents a significant step towards understanding how optimization of assembly conditions for surface-mediated LbL delivery can promote transfection efficacy while reducing the processing and material required.

Translational Applications of Hydrogels

Advances in hydrogel technology have unlocked unique and valuable capabilities that are being applied to a diverse set of translational applications. Hydrogels perform functions relevant to a range of biomedical purposes-they can deliver drugs or cells, regenerate hard and soft tissues, adhere to wet tissues, prevent bleeding, provide contrast during imaging, protect tissues or organs during radiotherapy, and improve the biocompatibility of medical implants. These capabilities make hydrogels useful for many distinct and pressing diseases and medical conditions and even for less conventional areas such as environmental engineering. In this review, we cover the major capabilities of hydrogels, with a focus on the novel benefits of injectable hydrogels, and how they relate to translational applications in medicine and the environment. We pay close attention to how the development of contemporary hydrogels requires extensive interdisciplinary collaboration to accomplish highly specific and complex biological tasks that range from cancer immunotherapy to tissue engineering to vaccination. We complement our discussion of preclinical and clinical development of hydrogels with mechanical design considerations needed for scaling injectable hydrogel technologies for clinical application. We anticipate that readers will gain a more complete picture of the expansive possibilities for hydrogels to make practical and impactful differences across numerous fields and biomedical applications.

Polymeric Delivery of Therapeutic Nucleic Acids

The advent of genome editing has transformed the therapeutic landscape for several debilitating diseases, and the clinical outlook for gene therapeutics has never been more promising. The therapeutic potential of nucleic acids has been limited by a reliance on engineered viral vectors for delivery. Chemically defined polymers can remediate technological, regulatory, and clinical challenges associated with viral modes of gene delivery. Because of their scalability, versatility, and exquisite tunability, polymers are ideal biomaterial platforms for delivering nucleic acid payloads efficiently while minimizing immune response and cellular toxicity. While polymeric gene delivery has progressed significantly in the past four decades, clinical translation of polymeric vehicles faces several formidable challenges. The aim of our Account is to illustrate diverse concepts in designing polymeric vectors towards meeting therapeutic goals of in vivo and ex vivo gene therapy. Here, we highlight several classes of polymers employed in gene delivery and summarize the recent work on understanding the contributions of chemical and architectural design parameters. We touch upon characterization methods used to visualize and understand events transpiring at the interfaces between polymer, nucleic acids, and the physiological environment. We conclude that interdisciplinary approaches and methodologies motivated by fundamental questions are key to designing high-performing polymeric vehicles for gene therapy.

Polyelectrolyte Multilayers on Soft Colloidal Nanosurfaces: A New Life for the Layer-By-Layer Method

The Layer-by-Layer (LbL) method is a well-established method for the assembly of nanomaterials with controlled structure and functionality through the alternate deposition onto a template of two mutual interacting molecules, e.g., polyelectrolytes bearing opposite charge. The current development of this methodology has allowed the fabrication of a broad range of systems by assembling different types of molecules onto substrates with different chemical nature, size, or shape, resulting in numerous applications for LbL systems. In particular, the use of soft colloidal nanosurfaces, including nanogels, vesicles, liposomes, micelles, and emulsion droplets as a template for the assembly of LbL materials has undergone a significant growth in recent years due to their potential impact on the design of platforms for the encapsulation and controlled release of active molecules. This review proposes an analysis of some of the current trends on the fabrication of LbL materials using soft colloidal nanosurfaces, including liposomes, emulsion droplets, or even cells, as templates. Furthermore, some fundamental aspects related to deposition methodologies commonly used for fabricating LbL materials on colloidal templates together with the most fundamental physicochemical aspects involved in the assembly of LbL materials will also be discussed.

Build-Up of a 3D Organogel Network within the Bilayer Shell of Nanoliposomes. A Novel Delivery System for Vitamin D3: Preparation, Characterization, and Physicochemical Stability

The inherent thermodynamic instability of liposomes during production and storage has limited their widespread applications. Therefore, a novel structure of food-grade nanoliposomes stabilized by a 3D organogel network within the bilayer shell was developed through the extrusion process and successfully applied to encapsulate vitamin D₃. A huge flocculation and a significant reduction of zeta potential (-17 mV) were observed in control nanoliposomes (without the organogel shell) after 2 months of storage at 4 °C, while the sample with a gelled bilayer showed excellent stability with a particle diameter of 105 nm and a high negative zeta potential (-63.4 mV), even after 3 months. The development of spherical vesicles was confirmed by TEM. Interestingly, the gelled bilayer shell led to improved stability against osmotically active divalent salt ions. Electron paramagnetic resonance confirmed the higher rigidity of the shell bilayer upon gelation. The novel liposome offered a dramatic increase in encapsulation efficiency and loading of vitamin D₃ compared to those of control.

Lipidome-based Targeting of STAT3-driven Breast Cancer Cells Using Poly-l-glutamic Acid-coated Layer-by-Layer Nanoparticles

The oncogenic transcription factor STAT3 is aberrantly activated in 70% of breast cancers, including nearly all triple-negative breast cancers (TNBCs). Because STAT3 is difficult to target directly, we considered whether metabolic changes driven by activated STAT3 could provide a therapeutic opportunity. We found that STAT3 prominently modulated several lipid classes, with most profound effects on N-acyl taurine and arachidonic acid, both of which are involved in plasma membrane remodeling. To exploit these metabolic changes therapeutically, we screened a library of layer-by-layer (LbL) nanoparticles (NPs) differing in the surface layer that modulates interactivity with the cell membrane. We found that poly-l-glutamic acid (PLE)-coated NPs bind to STAT3-transformed breast cancer cells with 50% greater efficiency than to nontransformed cells, and the heightened PLE-NP binding to TNBC cells was attenuated by STAT3 inhibition. This effect was also observed in densely packed three-dimensional breast cancer organoids. As STAT3-transformed cells show greater resistance to cytotoxic agents, we evaluated whether enhanced targeted delivery via PLE-NPs would provide a therapeutic advantage. We found that cisplatin-loaded PLE-NPs induced apoptosis of STAT3-driven cells at lower doses compared with both unencapsulated cisplatin and cisplatin-loaded nontargeted NPs. In addition, because radiation is commonly used in breast cancer treatment, and may alter cellular lipid distribution, we analyzed its effect on PLE-NP-cell binding. Irradiation of cells enhanced the STAT3-targeting properties of PLE-NPs in a dose-dependent manner, suggesting potential synergies between these therapeutic modalities. These findings suggest that cellular lipid changes driven by activated STAT3 may be exploited therapeutically using unique LbL NPs.

Overcharging of polyelectrolyte complexes: an entropic phenomenon

Overcharging in complex coacervation, in which a polyelectrolyte complex coacervate (PEC) initially containing equal moles of the cationic and anionic monomers absorbs a large excess of one type of polyelectrolyte species, is predicted using a recently developed thermodynamic model describing complexation through a combination of reversible ion binding on the chains and long-range electrostatic correlations. We show that overcharging is favored roughly equally by the translational entropy of released counterions and the binding entropy of polyelectrolytes in the polyelectrolyte complex, thus helping resolve competing explanations for overcharging in the literature. We find that the extent of overcharging is non-monotonic in the concentration of added salt and increases with both strength of ion-pairing between polyions and chain hydrophobicity. The predicted extent of overcharging of the PEC is directly compared with that of multilayers made of poly(diallyldimethylammonium), PDADMA, and poly(styrene-sulfonate), PSS, overcompensated by the polycation in two different salts: KBr and NaCl. Accounting for the specificity of salt ion interactions with the polyelectrolytes, we find good qualitative agreement between theory and experiment.

Networks of High Aspect Ratio Particles to Direct Colloidal Assembly Dynamics and Cellular Interactions

Injectable colloids that self-assemble into three-dimensional networks are promising materials for applications in regenerative engineering, as they create open systems for cellular infiltration, interaction, and activation. However, most injectable colloids have spherical morphologies, which lack the high material-biology contact areas afforded by higher aspect ratio materials. To address this need, injectable high aspect ratio particles (HARPs) were developed that form three-dimensional networks to enhance scaffold assembly dynamics and cellular interactions. HARPs were functionalized for tunable surface charge through layer-by-layer electrostatic assembly. Positively charged Chitosan-HARPs had improved particle suspension dynamics when compared to spherical particles or negatively charged HARPs. Chit-HARPs were used to improve the suspension dynamics and viability of MIN6 cells in three-dimensional networks. When combined with negatively charged gelatin microsphere (GelMS) porogens, Chit-HARPs reduced GelMS sedimentation and increased overall network suspension, due to a combination of HARP network formation and electrostatic interactions. Lastly, HARPs were functionalized with fibroblast growth factor 2 (FGF2) to highlight their use for growth factor delivery. FGF2-HARPs increased fibroblast proliferation through a combination of 3D scaffold assembly and growth factor delivery. Taken together, these studies demonstrate the development and diverse uses of high aspect ratio particles as tunable injectable scaffolds for applications in regenerative engineering.

Electrostatic Conjugation of Nanoparticle Surfaces with Functional Peptide Motifs

We report the surface functionalization of anionic layer by layer nanoparticles (LbL NPs) with cationic tumor-penetrating peptides (TPPs) via electrostatic adsorption while retaining particle stability and charge characteristics. This strategy eliminates the need for structural modifications of the peptide and enables facile functionalization of surface chemistries difficult to modify or inaccessible via covalent conjugation strategies. We show that both carboxylated and sulfated LbL NPs are able to accommodate linear and cyclic TPPs and used fluorescence-based detection assays to quantify peptide loading per NP. We also demonstrate that TPP activity is retained upon adsorption, implying sufficient numbers of peptides take on the appropriate surface orientation, enabling efficient uptake of functionalized NPs in vitro, as characterized via flow cytometry and deconvolution microscopy. Overall, we believe that this strategy will serve as a broadly applicable approach to impart electrostatically assembled NPs with bioactive peptide motifs.

Arginine-Based Poly(I:C)-Loaded Nanocomplexes for the Polarization of Macrophages Toward M1-Antitumoral Effectors

Background: Tumor-associated macrophages (TAMs), with M2-like immunosuppressive profiles, are key players in the development and dissemination of tumors. Hence, the induction of M1 pro-inflammatory and anti-tumoral states is critical to fight against cancer cells. The activation of the endosomal toll-like receptor 3 by its agonist poly(I:C) has shown to efficiently drive this polarization process. Unfortunately, poly(I:C) presents significant systemic toxicity, and its clinical use is restricted to a local administration. Therefore, the objective of this work has been to facilitate the delivery of poly(I:C) to macrophages through the use of nanotechnology, that will ultimately drive their phenotype toward pro-inflammatory states.

Methods: Poly(I:C) was complexed to arginine-rich polypeptides, and then further enveloped with an anionic polymeric layer either by film hydration or incubation. Physicochemical characterization of the nanocomplexes was conducted by dynamic light scattering and transmission electron microscopy, and poly(I:C) association efficiency by gel electrophoresis. Primary human-derived macrophages were used as relevant in vitro cell model. Alamar Blue assay, ELISA, PCR and flow cytometry were used to determine macrophage viability, polarization, chemokine secretion and uptake of nanocomplexes. The cytotoxic activity of pre-treated macrophages against PANC-1 cancer cells was assessed by flow cytometry.

Results: The final poly(I:C) nanocomplexes presented sizes lower than 200 nm, with surface charges ranging from +40 to −20 mV, depending on the envelopment. They all presented high poly(I:C) loading values, from 12 to 50%, and great stability in cell culture media. In vitro, poly(I:C) nanocomplexes were highly taken up by macrophages, in comparison to the free molecule. Macrophage treatment with these nanocomplexes did not reduce their viability and efficiently stimulated the secretion of the T-cell recruiter chemokines CXCL10 and CCL5, of great importance for an effective anti-tumor immune response. Finally, poly(I:C) nanocomplexes significantly increased the ability of treated macrophages to directly kill cancer cells.

Conclusion: Overall, these enveloped poly(I:C) nanocomplexes might represent a therapeutic option to fight cancer through the induction of cytotoxic M1-polarized macrophages.

Layer-by-Layer Biomaterials for Drug Delivery

Controlled drug delivery formulations have revolutionized treatments for a range of health conditions. Over decades of innovation, layer-by-layer (LbL) self-assembly has emerged as one of the most versatile fabrication methods used to develop multifunctional controlled drug release coatings. The numerous advantages of LbL include its ability to incorporate and preserve biological activity of therapeutic agents; coat multiple substrates of all scales (e.g., nanoparticles to implants); and exhibit tuned, targeted, and/or responsive drug release behavior. The functional behavior of LbL films can be related to their physicochemical properties. In this review, we highlight recent advances in the development of LbL-engineered biomaterials for drug delivery, demonstrating their potential in the fields of cancer therapy, microbial infection prevention and treatment, and directing cellular responses. We discuss the various advantages of LbL biomaterial design for a given application as demonstrated through in vitro and in vivo studies.

The role of critical micellization concentration in efficacy and toxicity of supramolecular polymers

The inception and development of supramolecular chemistry have provided a vast library of supramolecular structures and materials for improved practice of medicine. In the context of therapeutic delivery, while supramolecular nanostructures offer a wide variety of morphologies as drug carriers for optimized targeting and controlled release, concerns are often raised as to how their morphological stability and structural integrity impact their in vivo performance. After intravenous (i.v.) administration, the intrinsic reversible and dynamic feature of supramolecular assemblies may lead them to dissociate upon plasma dilution to a concentration below their critical micellization concentration (CMC). As such, CMC represents an important characteristic for supramolecular biomaterials design, but its pharmaceutical role remains elusive. Here, we report the design of a series of self-assembling prodrugs (SAPDs) that spontaneously associate in aqueous solution into supramolecular polymers (SPs) with varying CMCs. Two hydrophobic camptothecin (CPT) molecules were conjugated onto oligoethylene-glycol (OEG)-decorated segments with various OEG repeat numbers (2, 4, 6, 8). Our studies show that the lower the CMC, the lower the maximum tolerated dose (MTD) in rodents. When administrated at the same dosage of 10 mg/kg (CPT equivalent), SAPD 1, the one with the lowest CMC, shows the best efficacy in tumor suppression. These observations can be explained by the circulation and dissociation of SAPD SPs and the difference in molecular and supramolecular distribution between excretion and organ uptake. We believe these findings offer important insight into the role of supramolecular stability in determining their therapeutic index and in vivo efficacy.

Tuning Nanoparticle Interactions with Ovarian Cancer through Layer-by-Layer Modification of Surface Chemistry

Nanoparticle surface chemistry is a fundamental engineering parameter that governs tumor-targeting activity. Electrostatic assembly generates controlled polyelectrolyte complexes through the process of adsorption and charge overcompensation utilizing synthetic polyions and natural biomacromolecules; it can yield films with distinctive hydration, charge, and presentation of functional groups. Here, we used electrostatic layer-by-layer (LbL) assembly to screen 10 different surface chemistries for their ability to preferentially target human ovarian cancer in vitro. Our screen identified that poly-l-aspartate, poly-l-glutamate, and hyaluronate-coated LbL nanoparticles have striking specificity for ovarian cancer, while sulfated poly(β-cyclodextrin) nanoparticles target noncancerous stromal cells. We validated top candidates for tumor-homing ability with a murine model of metastatic disease and with patient-derived ovarian cancer spheroids. Nanoparticle surface chemistry also influenced subcellular trafficking, indicating strategies to target the cell membrane, caveolae, and perinuclear vesicles. Our results confirm LbL is a powerful tool to systematically engineer nanoparticles and achieve specific targeting.

Theranostic Layer-by-Layer Nanoparticles for Simultaneous Tumor Detection and Gene Silencing

Layer-by-layer nanoparticles (NPs) are modular drug delivery vehicles that incorporate multiple functional materials through sequential deposition of polyelectrolytes onto charged nanoparticle cores. Herein, we combined the multicomponent features and tumor targeting capabilities of layer-by-layer assembly with functional biosensing peptides to create a new class of nanotheranostics. These NPs encapsulate a high weight percentage of siRNA while also carrying a synthetic biosensing peptide on the surface that is cleaved into a urinary reporter upon exposure to specific proteases overexpressed in the tumor microenvironment. Importantly, this biosensor reports back on a molecular signature characteristic to metastatic tumors and associated with poor prognosis, MMP9 protease overexpression. This nanotheranostic mediates noninvasive urinary-based diagnostics in mouse models of three different cancers with simultaneous gene silencing in flank and metastatic mouse models of ovarian cancer.

Mesenchymal stem cell-derived microvesicles mediate BMP2 gene delivery and enhance bone regeneration

Microvesicles–polyethyleneimine/pDNA formed via layer-by-layer self-assembly increase the delivery of hBMP2 plasmids and enhance bone repair.

A Biocompatible Multilayer Film from an Asymmetric Picolinium-Containing Polycation with Fast Visible-Light/NIR-Degradability

Finely tuning the photodegradation behavior of the layer-by-layer (LbL) film from the view of controlling the chemical structure of the film-building polymer is still a challenge in related fields. To meet this requirement, a photodegradable polymer (P1) is rationally designed for assembling a visible-light-degradable multilayer film with polystyrene sulfonate (PSS). Compared with similar photopolymers (P2 and P3), this asymmetric picolinium-containing polymer can significantly enhance the degradation rate of as-prepared LbL films; under the same degradation condition, the degradation rate of (P1/PSS)10 is 3 and 6.6 times that of (P2/PSS)10 and (P3/PSS)10, respectively. Moreover, near-infrared light (NIR) is available for triggering the degradation of this film with the assistance of upconversion nanoparticles of YbTm@Lu. The cell cytotoxicity and cell proliferation experiments reveal that P1 is nontoxic and favorable for cell proliferation at concentrations of up to 500 μg mL^-1 . As for (PSS/P1)10 films, the ratio of cell number of these two samples ((PSS/P1)10 modified: photodegraded) increases dramatically and reaches about 1.67:1 after 72 h incubation. On the basis of these results, it is anticipated that P1 and this LbL film is an exceptional candidate for visible-light/NIR degradable materials in materials and biological science, medicine, and optics.

pH-Responsive polyelectrolyte coated gadolinium oxide-doped mesoporous silica nanoparticles (Gd2O3@MSNs) for synergistic drug delivery and magnetic resonance imaging enhancement

Theranostic platforms that combine therapeutic and imaging modalities have received increasing interest.