Rapid coating of surfaces with functionalized nanoparticles for regulation of cell behavior

PDMS nanoparticles-decorated PDMS substrate promotes adhesion, proliferation and differentiation of skin cells

Polydimethylsiloxane (PDMS) is known to be a common substrate for various cell culture-based applications. However, native PDMS is not very conducive for cell culture and hence, surface modification via cell adhesion moieties is generally needed to make it suitable especially for long-term cell culture. To address this issue, we propose to coat PDMS nanoparticles (NPs) on the surface of PDMS film to improve adhesion, proliferation and differentiation of skin cells. The proposed modification strategy introduces necessary nanotopography without altering the surface chemical properties of PDMS. Due to resemblance in the mechanical properties of PDMS with skin, PDMS NPs can recreate the native extracellular nanoenvironment of skin on the PDMS surface and provide anchoring sites for skin cells to adhere and grow. Human keratinocytes, representing 95% of the epidermal skin cells maintained their characteristic well-spread morphology with the formation of interconnected cell-sheets on this coated PDMS surface. Moreover, our in vitro immunofluorescence studies confirmed expression of distinctive epidermal protein markers on the coated surface indicating close resemblance with the native skin epidermis. Conclusively, our findings suggest that introducing nanotopography via PDMS NPs can be an effective strategy for emulating the native cellular functions of keratinocytes on PDMS based cell culture devices.

DNA/Magnetic Nanoparticles Composite to Attenuate Glass Surface Nanotopography for Enhanced Mesenchymal Stem Cell Differentiation

Mesenchymal stem cells (MSCs) have extensive pluripotent potential to differentiate into various cell types, and thus they are an important tool for regenerative medicine and biomedical research. In this work, the differentiation of hTERT-transduced adipose-derived MSCs (hMSCs) into chondrocytes, adipocytes and osteoblasts on substrates with nanotopography generated by magnetic iron oxide nanoparticles (MNPs) and DNA was investigated. Citrate-stabilized MNPs were synthesized by the chemical co-precipitation method and sized around 10 nm according to microscopy studies. It was shown that MNPs@DNA coatings induced chondrogenesis and osteogenesis in hTERT-transduced MSCs. The cells had normal morphology and distribution of actin filaments. An increase in the concentration of magnetic nanoparticles resulted in a higher surface roughness and reduced the adhesion of cells to the substrate. A glass substrate modified with magnetic nanoparticles and DNA induced active chondrogenesis of hTERT-transduced MSC in a twice-diluted differentiation-inducing growth medium, suggesting the possible use of nanostructured MNPs@DNA coatings to obtain differentiated cells at a reduced level of growth factors.

Multistage signal-interactive nanoparticles improve tumor targeting through efficient nanoparticle-cell communications

Communication between biological components is critical for homeostasis maintenance among the convergence of complicated bio-signals. For therapeutic nanoparticles (NPs), the general lack of effective communication mechanisms with the external cellular environment causes loss of homeostasis, resulting in deprived autonomy, severe macrophage-mediated clearance, and limited tumor accumulation. Here, we develop a multistage signal-interactive system on porous silicon particles through integrating the Self-peptide and Tyr-Ile-Gly-Ser-Arg (YIGSR) peptide into a hierarchical chimeric signaling interface with “don’t eat me” and “eat me” signals. This biochemical transceiver can act as both the signal receiver for amantadine to achieve NP transformation and signal conversion as well as the signal source to present different signals sequentially by reversible self-mimicking. Compared with the non-interactive controls, these signal-interactive NPs loaded with AS1411 and tanespimycin (17-AAG) as anticancer drugs improve tumor targeting 2.8-fold and tumor suppression 6.5-fold and showed only 51% accumulation in the liver with restricted hepatic injury.

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Constructing a signal-interactive NP system improves NP-cell communication efficiency

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Functional chimeric peptide design enables orderly integrating of multiple signal modules

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Signal-interactive NPs reduce liver accumulation and promote tumor targeting

Biological Safe Gold Nanoparticle-Modified Dental Aligner Prevents the Porphyromonas gingivalis Biofilm Formation

Oral microbiology could directly influence overall health. Porphyromonas gingivalis (P. gingivalis) is a highly pathogenic bacterium that causes periodontitis and other related systematic diseases, including Alzheimer's disease. Orthodontic devices (e.g., invisalign aligner) is commonly used in populations with periodontitis who are also at a high risk of systematic diseases. In this study, newly explored antibacterial 4,6-diamino-2-pyrimidinethiol-modified gold nanoparticles (AuDAPT) were coated onto aligners. The coated aligners showed favorable antibacterial activity against P. gingivalis. In the presence of the coated aligner, the number of planktonic cells was decreased, and biofilm formation was prevented. This material also showed favorable biocompatibility in vivo and in vitro. This study reveals a new method for treating oral P. gingivalis by coating aligners with AuDAPT, which has typical advantages compared to other treatments for both periodontitis and related systematic diseases.

Tailored Functional Surfaces Using Nanoparticle and Protein "Nanobrick" Coatings

Surface properties are an essential feature in a wide range of functional materials. In this article, we summarize strategies developed in our group that employ nanoparticles and proteins as nanobricks to create thin-film coatings on surfaces. These coatings contain tailorable surface functionality based on the properties of the predesigned nanobricks, parlaying both the chemical and structural features of the precursor particles and proteins. This strategy is versatile, providing the rapid generation of both uniform and patterned coatings that provide "plug-and-play" customizable surfaces for materials and biomedical applications.

Vanadium Dioxide Nanocoating Induces Tumor Cell Death through Mitochondrial Electron Transport Chain Interruption

A biomaterials surface enabling the induction of tumor cell death is particularly desirable for implantable biomedical devices that directly contact tumor tissues. However, this specific antitumor feature is rarely found. Consequently, an antitumor-cell nanocoating comprised of vanadium dioxide (VO2) prepared by customized reactive magnetron sputtering has been proposed, and its antitumor-growth capability has been demonstrated using human cholangiocarcinoma cells. The results reveal that the VO2 nanocoating is able to interrupt the mitochondrial electron transport chain and then elevate the intracellular reactive oxygen species levels, leading to the collapse of the mitochondrial membrane potential and the destruction of cell redox homeostasis. Indeed, this chain reaction can effectively trigger oxidative damage in the cholangiocarcinoma cells. Additionally, this study has provided new insights into designing a tumor-cell-inhibited biomaterial surface, which is modulated by the mechanism of mitochondria-targeting tumor cell death.

Neurotrophin-mimicking peptides at the biointerface with gold respond to copper ion stimuli

The peptide fragments NGF_1-14 and BDNF_1-12, encompassing the N-terminal domains, respectively, of the proteins nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) were used in this study for the fabrication of a hybrid gold/peptide biointerface. These peptides mimic the Trk receptor activation of the respective whole protein - with a crucial role played by copper ions - and exhibit, in bulk solution, a pH-dependent capability to complex copper. We demonstrate here the maintenance of peptide-specific responses at different pH values as well as the copper binding also for the adlayers formed upon physisorption at the gold surface. The physicochemical properties, including viscoelastic behavior of the adlayer and competitive vs. synergic interactions in sequential adsorption processes, were addressed both experimentally, by quartz crystal microbalance with dissipation monitoring (QCM-D) and circular dichroism (CD), and theoretically, by molecular dynamics (MD) calculations. Proof-of work biological assays with the neuroblastoma SY-SH5H cell line demonstrated that the developed hybrid Au/peptide nanoplatforms are very promising for implementation in pH- and metal-responsive systems for application in nanomedicine.

Platelet-Facilitated Photothermal Therapy of Head and Neck Squamous Cell Carcinoma

Here, we present a platelet-facilitated photothermal tumor therapy (PLT-PTT) strategy, in which PLTs act as carriers for targeted delivery of photothermal agents to tumor tissues and enhance the PTT effect. Gold nanorods (AuNRs) were first loaded into PLTs by electroporation and the resulting AuNR-loaded PLTs (PLT-AuNRs) inherited long blood circulation and cancer targeting characteristics from PLTs and good photothermal property from AuNRs. Using a gene-knockout mouse model, we demonstrate that the administration of PLT-AuNRs and localizing laser irradiation could effectively inhibit the growth of head and neck squamous cell carcinoma (HNSCC). In addition, we found that the PTT treatment augmented PLT-AuNRs targeting to the tumor sites and in turn, improved the PTT effects in a feedback manner, demonstrating the unique self-reinforcing characteristic of PLT-PTT in cancer therapy.

Dual-Mode Mass Spectrometric Imaging for Determination of in Vivo Stability of Nanoparticle Monolayers

Effective correlation of the in vitro and in vivo stability of nanoparticle-based platforms is a key challenge in their translation into the clinic. Here, we describe a dual imaging method that site-specifically reports the stability of monolayer-functionalized nanoparticles in vivo. This approach uses laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) imaging to monitor the distributions of the nanoparticle core material and laser desorption/ionization mass spectrometry (LDI-MS) imaging to report on the monolayers on the nanoparticles. Quantitative comparison of the images reveals nanoparticle stability at the organ and suborgan level. The stability of particles observed in the spleen was location-dependent and qualitatively similar to in vitro studies. In contrast, in vivo stability of the nanoparticles in the liver differed dramatically from in vitro studies, demonstrating the importance of in vivo assessment of nanoparticle stability.

Universal Coating from Electrostatic Self-Assembly to Prevent Multidrug-Resistant Bacterial Colonization on Medical Devices and Solid Surfaces

We provide a facile and scalable strategy for preparing gold nanoparticles (AuNPs)-based antibacterial coating on a variety of surfaces through electrostatic self-assembly. AuNPs conjugated with 4,6-diamino-2-pyrimidinethiol (DAPT, not antibacterial by itself), AuDAPT, can form stable coating on different substrates made from polyethylene (PS), polyvinyl chloride (PVC), polypropylene (PP), polyethylene (PE), polydimethylsiloxane (PDMS), and SiO₂ in one step. Such a coating can efficiently eradicate pathogenic Gram-negative bacteria and even multidrug-resistant (MDR) mutants without causing any side-effect such as cytotoxicity, hemolysis, coagulation, and inflammation. We show that immobilized AuDAPT, instead of AuDAPT released from the substrate, is responsible for killing the bacteria and that the antimicrobial components do not enter into the environment to cause secondary contamination to breed drug resistance. Advantages for such coating include applicability on a broad range of surfaces, low cost, stability, high antibacterial efficiency, good biocompatibility, and low risk in antibiotics pollution; these advantages may be particularly helpful in preventing infections that involve medical devices.

Organic chemistry meets polymers, nanoscience, therapeutics and diagnostics

The atom-by-atom control provided by synthetic organic chemistry presents a means of generating new functional nanomaterials with great precision. Bringing together these two very disparate skill sets is, however, quite uncommon. This autobiographical review provides some insight into how my program evolved, as well as giving some idea of where we are going.

Quantitative Differentiation of Cell Surface-Bound and Internalized Cationic Gold Nanoparticles Using Mass Spectrometry

Differentiation between cell surface-bound and internalized nanoparticles is challenging yet essential for accurately quantifying cellular uptake. Here, we describe a versatile mass spectrometry-based method that allows separate quantification of both cell surface-bound and internalized nanoparticles. This rapid method uses tuned laser fluencies to selectively desorb and ionize cell surface-bound cationic gold nanoparticles from intact cells, providing quantification of external particles. Overall nanoparticle quantities are obtained from the cell lysates, with subtraction of external particles from the total amount providing quantification of taken-up nanoparticles. The utility of this strategy was demonstrated through simultaneous quantitative determination of how cell-surface proteoglycans influence nanoparticle binding and uptake into cells.

Biochemical and biomechanical drivers of cancer cell metastasis, drug response and nanomedicine

Metastasis, drug resistance and recurrence in cancer are regulated by the tumor microenvironment. This review describes recent advances in understanding how cancer cells respond to extracellular environmental cues via integrins, how to build engineered microenvironments to study these interactions in vitro and how nanomaterials can be used to detect and target tumor microenvironments.

The influence of the size and aspect ratio of anisotropic, porous CaCO3 particles on their uptake by cells

BACKGROUND

Recent reports highlighting the role of particle geometry have suggested that anisotropy can affect the rate and the pathway of particle uptake by cells. Therefore, we investigate the internalization by cells of porous calcium carbonate particles with different shapes and anisotropies.

RESULTS

We report here on a new method of the synthesis of polyelectrolyte coated calcium carbonate particles whose geometry was controlled by varying the mixing speed and time, pH value of the reaction solution, and ratio of the interacting salts used for particle formation. Uptake of spherical, cuboidal, ellipsoidal (with two different sizes) polyelectrolyte coated calcium carbonate particles was studied in cervical carcinoma cells. Quantitative data were obtained from the analysis of confocal laser scanning microscopy images.

CONCLUSIONS

Our results indicate that the number of internalized calcium carbonate particles depends on the aspect ratio of the particle, whereby elongated particles (higher aspect ratio) are internalized with a higher frequency than more spherical particles (lower aspect ratio). The total volume of internalized particles scales with the volume of the individual particles, in case equal amount of particles were added per cell.

Fabrication of functional nanofibers through post-nanoparticle functionalization

A facile method is developed to functionalize nanofiber surfaces with nanoparticles (NPs) through dithiocarbamate chemistry. Gold nanoparticles (AuNPs) and quantum dots (QDs) are immobilized on the nanofiber surface. These surfaces provide scaffolds for further supramolecular functionalization, as demonstrated through the Förster resonance energy transfer (FRET) pairing of QD-decorated fibers and fluorescent proteins.

Regulating exocytosis of nanoparticles via host-guest chemistry

Prolonged retention of internalized nanoparticulate systems inside cells improves their efficacy in imaging, drug delivery, and theranostic applications. Especially, regulating exocytosis of the nanoparticles is a key factor in the fabrication of effective nanocarriers for chemotherapeutic treatments but orthogonal control of exocytosis in the cellular environment is a major challenge. Herein, we present the first example of regulating exocytosis of gold nanoparticles (AuNPs), a model drug carrier, by using a simple host-guest supramolecular system. AuNPs featuring quaternary amine head groups were internalized into the cells through endocytosis. Subsequent in situ treatment of a complementary cucurbit[7]uril (CB[7]) to the amine head groups resulted in the AuNP-CB[7] complexation inside cells, rendering particle assembly. This complexation induced larger particle assemblies that remained sequestered in the endosomes, inhibiting exocytosis of the particles without any observed cytotoxicity.

An overview of nanotoxicity and nanomedicine research: principles, progress and implications for cancer therapy

The studies of nanomaterial-based drug delivery and nanotoxicity are closely interconnected.

Hybrid inverse opals for regulating cell adhesion and orientation

Cell adhesion and alignment are two important considerations in tissue engineering applications as they can regulate the subsequent cell proliferation activity and differentiation program. Although many effects have been applied to regulate the adhesion or alignment of cells by using physical and chemical methods, it is still a challenge to regulate these cell behaviors simultaneously. Here, we present novel substrates with tunable nanoscale patterned structures for regulating the adhesion and alignment of cells. The substrates with different degrees of pattern orientation were achieved by customizing the amount of stretching applied to polymer inverse opal films. Cells cultured on these substrates showed an adjustable morphology and alignment. Moreover, soft hydrogels, which have poor plasticity and are difficult to cast into patterned structures, were applied to infiltrate the inverse opal structure. We demonstrated that the adhesion ratio of cells could be regulated by these hybrid substrates, as well as adjusting the cell morphology and alignment. These features of functional inverse opal substrates make them suitable for important applications in tissue engineering.