Nanotextured polymer substrates show enhanced cancer cell isolation and cell culture

Dielectric Response of ZnO/PMMA Nanocomposites with Atmospheric Pressure Plasma-Modified Surfaces

In this work, the effect of etching the surface of polymer matrix nanocomposites with atmospheric pressure plasma targeting to achieve enhanced dielectric properties was investigated. Polymer nanocomposites, with varying reinforcing phase content, were modified by atmospheric-pressure plasma resulting in an increase in the surface filler's concentration. Polymethyl methacrylate (PMMA) matrix nanocomposites reinforced with zinc oxide (ZnO) nanoparticles were prepared and dielectrically studied as a function of the nanoparticle content and the plasma modified surfaces. The electrical response of the composite systems was studied by means of Broadband Dielectric Spectroscopy (BDS) over a wide range of temperatures and frequencies. The dielectric permittivity increased with the embedded phase content and with plasma surface treatment. Energy density followed the same trend as dielectric permittivity, and the plasma-treated nanocomposite with the higher ZnO content exhibited approximately 27% higher energy density compared to the unreinforced matrix.

Surface Engineering of a Bioartificial Membrane for Its Application in Bioengineering Devices

Membrane technology is playing a crucial role in cutting-edge innovations in the biomedical field. One such innovation is the surface engineering of a membrane for enhanced longevity, efficient separation, and better throughput. Hence, surface engineering is widely used while developing membranes for its use in bioartificial organ development, separation processes, extracorporeal devices, etc. Chemical-based surface modifications are usually performed by functional group/biomolecule grafting, surface moiety modification, and altercation of hydrophilic and hydrophobic properties. Further, creation of micro/nanogrooves, pillars, channel networks, and other topologies is achieved to modify physio-mechanical processes. These surface modifications facilitate improved cellular attachment, directional migration, and communication among the neighboring cells and enhanced diffusional transport of nutrients, gases, and waste across the membrane. These modifications, apart from improving functional efficiency, also help in overcoming fouling issues, biofilm formation, and infection incidences. Multiple strategies are adopted, like lysozyme enzymatic action, topographical modifications, nanomaterial coating, and antibiotic/antibacterial agent doping in the membrane to counter the challenges of biofilm formation, fouling challenges, and microbial invasion. Therefore, in the current review, we have comprehensibly discussed different types of membranes, their fabrication and surface modifications, antifouling/antibacterial strategies, and their applications in bioengineering. Thus, this review would benefit bioengineers and membrane scientists who aim to improve membranes for applications in tissue engineering, bioseparation, extra corporeal membrane devices, wound healing, and others.

Nano-liter perfusion microfluidic device made entirely by two-photon polymerization for dynamic cell culture with easy cell recovery

Polydimethylsiloxane (PDMS) has been the material of choice for microfluidic applications in cell biology for many years, with recent advances encompassing nano-scaffolds and surface modifications to enhance cell-surface interactions at nano-scale. However, PDMS has not previously been amenable to applications which require complex geometries in three dimensions for cell culture device fabrication in the absence of additional components. Further, PDMS microfluidic devices have limited capacity for cell retrieval following culture without severely compromising cell health. This study presents a designed and entirely 3D-printed microfluidic chip (8.8 mm × 8.2 mm × 3.6 mm) using two-photon polymerization (2PP). The 'nest' chip is composed of ten channels that deliver sub-microliter volume flowrates (to ~ 600 nL/min per channel) to 10 individual retrievable cell sample 'cradles' that interlock with the nest to create the microfluidic device. Computational fluid dynamics modelling predicted medium flow in the device, which was accurately validated by real-time microbead tracking. Functional capability of the device was assessed, and demonstrated the capability to deliver culture medium, dyes, and biological molecules to support cell growth, staining and cell phenotype changes, respectively. Therefore, 2PP 3D-printing provides the precision needed for nanoliter fluidic devices constructed from multiple interlocking parts for cell culture application.

Circulating Tumor Cells for Glioma

Liquid biopsy has entered clinical applications for several cancers, including metastatic breast, prostate, and colorectal cancer for CTC enumeration and NSCLC for EGFR mutations in ctDNA, and has improved the individualized treatment of many cancers, but relatively little progress has been made in validating circulating biomarkers for brain malignancies. So far, data on circulating tumor cells about glioma are limited, the application of circulating tumor cells as biomarker for glioma patients has only just begun. This article reviews the research status and application prospects of circulating tumor cells in gliomas. Several detection methods and research results of circulating tumor cells about clinical research in gliomas are briefly discussed. The wide application prospect of circulating tumor cells in glioma deserves further exploration, and the research on more sensitive and convenient detection methods is necessary.

Recent advances in microfluidic technologies for circulating tumor cells: enrichment, single-cell analysis, and liquid biopsy for clinical applications

Circulating tumor cells (CTCs) detach from primary or metastatic lesions and circulate in the peripheral blood, which is considered to be the cause of distant metastases. CTC analysis in the form of liquid biopsy, enumeration and molecular analysis provide significant clinical information for cancer diagnosis, prognosis and therapeutic strategies. Despite the great clinical value, CTC analysis has not yet entered routine clinical practice due to lack of efficient technologies to perform CTC isolation and single-cell analysis. Taking the rarity and inherent heterogeneity of CTCs into account, reliable methods for CTC isolation and detection are in urgent demand for obtaining valuable information on cancer metastasis and progression from CTCs. Microfluidic technology, featuring microfabricated structures, can precisely control fluids and cells at the micrometer scale, thus making itself a particularly suitable method for rare CTC manipulation. Besides the enrichment function, microfluidic chips can also realize the analysis function by integrating multiple detection technologies. In this review, we have summarized the recent progress in CTC isolation and detection using microfluidic technologies, with special attention to emerging direct enrichment and enumeration in vivo. Further, few insights into single CTC molecular analysis are also demonstrated. We have provided a review of potential clinical applications of CTCs, ranging from early screening and diagnosis, tumor progression and prognosis, treatment and resistance monitoring, to therapeutic evaluation. Through this review, we conclude that the clinical utility of CTCs will be expanded as the isolation and analysis techniques are constantly improving.

Doxorubicin hydrochloride loaded nanotextured films as a novel drug delivery platform for ovarian cancer treatment

An approach for cancer treatment is modulation of tumor microenvironment. Based on the role of extracellular matrix in cell modulation, fabrication of textured materials mimicking extracellular matrix could provide novel opportunities such as determining cancer cell behaviour. With this background, in this work, we have fabricated doxorubicin hydrochloride loaded nanotextured films which promote topographical attachment of cancer cells to film surface, and eliminate cells by release of the anti-cancer drug encapsulated within the films. These films are designed to be placed during surgical removal of the tumor with the intent to prevent ovarian cancer recurrence by capturing cancer cell residuals. With this aim, hemispherical protrusion shaped surface textures were acquired using colloidal lithography technique using 280 nm, 210 nm or 99 nm polystyrene particles. Once moulds were formed, nanotextured films were obtained by casting water-in-oil stable polycaprolactone emulsions encapsulating doxorubicin hydrochloride. Films were then characterized, and evaluated as drug delivery systems. According to results, we found that template morphologies were successfully transferred to films by atomic force microscopy studies. Hydrophilic surfaces were formed with contact angle values around 40°. In-vitro drug release studies indicated that nanotextured films best fit into the Higuchi model, and ∼30% of the drug is released from the films within 60 days. Cell culture results indicated increases in the attachment and viability of human ovarian cancer cells to nanotextured surfaces, particularly to the film fabricated using 99 nm particles. Our results demonstrated that delivery of anti-cancer drugs by use of nanotextured materials could be efficient in cancer therapy, and may offer new possibilities for cancer treatment.

Recent Advances in Microfluidic Platforms Applied in Cancer Metastasis: Circulating Tumor Cells' (CTCs) Isolation and Tumor-On-A-Chip

Cancer remains the leading cause of death worldwide despite the enormous efforts that are made in the development of cancer biology and anticancer therapeutic treatment. Furthermore, recent studies in oncology have focused on the complex cancer metastatic process as metastatic disease contributes to more than 90% of tumor-related death. In the metastatic process, isolation and analysis of circulating tumor cells (CTCs) play a vital role in diagnosis and prognosis of cancer patients at an early stage. To obtain relevant information on cancer metastasis and progression from CTCs, reliable approaches are required for CTC detection and isolation. Additionally, experimental platforms mimicking the tumor microenvironment in vitro give a better understanding of the metastatic microenvironment and antimetastatic drugs' screening. With the advancement of microfabrication and rapid prototyping, microfluidic techniques are now increasingly being exploited to study cancer metastasis as they allow precise control of fluids in small volume and rapid sample processing at relatively low cost and with high sensitivity. Recent advancements in microfluidic platforms utilized in various methods for CTCs' isolation and tumor models recapitulating the metastatic microenvironment (tumor-on-a-chip) are comprehensively reviewed. Future perspectives on microfluidics for cancer metastasis are proposed.

Three-dimensional (3D) hierarchical oxygen plasma micro/nanostructured polymeric substrates for selective enrichment of cancer cells from mixtures with normal ones

The enrichment of cancer cell population when in mixtures with normal ones is of great importance for cancer diagnosis. In this work, poly(methyl methacrylate) films have been processed applying different oxygen plasma conditions to fabricate surfaces with structure height ranging from 22 to more than 2000 nm. The surfaces were then evaluated with respect to adhesion and proliferation of both normal and cancer human cells. In particular, normal skin and lung fibroblasts, and four different cancer cell lines, A431 (skin cancer), HT1080 (fibrosarcoma), A549 (lung cancer), and PC3 (prostate cancer), have been employed. It was found that adhesion and proliferation of cancer cells was favored when cultured onto the hierarchical micro/nanostructured surfaces as compared to untreated ones with the maximum values obtained for substrates treated at -100 V for 3 min. On the other hand, although the adhesion of normal fibroblasts was not influenced by the micro/nanostructured surfaces, their morphology and proliferation was significantly impaired, especially after 3-day culture on these surfaces. The reduced proliferation rate of adherent fibroblasts was linked to reduced focal points formation, as it was verified through vinculin staining, and not to apoptosis. The micro/nanostructured surfaces prepared with plasma treatment at -100 V for 3 min (hierarchical topography with mean height of ∼800 nm) were selected as substrates for normal and cancer cell co-culture experiments. It was found that 25-80 times enrichment of cancer over the normal cells was achieved on the nanostructured surfaces after 3-day culture, while it was 5-8 times lower on the untreated ones. It should be noticed that this is the first time such high enrichment ratios are achieved without implementing surfaces modified with binding molecules specific for cancer cells. Thus, the nanostructured surfaces hold a strong promise as culture substrates for separation and enrichment of cancer cells from mixtures with normal ones that should find application in cancer diagnostics.

Microfluidic technologies for circulating tumor cell isolation

Metastasis is the main cause of tumor-related death, and the dispersal of tumor cells through the circulatory system is a critical step in the metastatic process. Early detection and analysis of circulating tumor cells (CTCs) is therefore important for early diagnosis, prognosis, and effective treatment of cancer, enabling favorable clinical outcomes in cancer patients. Accurate and reliable methods for isolating and detecting CTCs are necessary to obtain this clinical information. Over the past two decades, microfluidic technologies have demonstrated great potential for isolating and detecting CTCs from blood. The present paper reviews current advanced microfluidic technologies for isolating CTCs based on various biological and physical principles, and discusses their fundamental advantages and drawbacks for subsequent cellular and molecular assays. Owing to significant genetic heterogeneity among CTCs, microfluidic technologies for isolating individual CTCs have recently been developed. We discuss these single-cell isolation methods, as well as approaches to overcoming the limitations of current microfluidic CTC isolation technologies. Finally, we provide an overview of future innovative microfluidic platforms.

Circulating Tumor Cells: From Theory to Nanotechnology-Based Detection

Cancer stem cells with stem-cell properties are regarded as tumor initiating cells. Sharing stem-cell properties, circulating tumor cells (CTCs) are responsible for the development of metastasis, which significant affects CTC analysis in clinical practice. Due to their extremely low occurrence in blood, however, it is challenging to enumerate and analyze CTCs. Nanotechnology is able to address the problems of insufficient capture efficiency and low purity of CTCs owing to the unique structural and functional properties of nanomaterials, showing strong promise for CTC isolation and detection. In this review, we discuss the role of stem-like CTCs in metastases, provide insight into recent progress in CTC isolation and detection approaches using various nanoplatforms, and highlight the role of nanotechnology in the advancement of CTC research.

Enhanced proliferation of PC12 neural cells on untreated, nanotextured glass coverslips

Traumatic injury to the central nervous system is a significant health problem. There is no effective treatment available partly because of the complexity of the system. Implementation of multifunctional micro- and nano-device based combinatorial therapeutics can provide biocompatible and tunable approaches to perform on-demand release of specific drugs. This can help the damaged cells to improve neuronal survival, regeneration of axons, and their reconnection to appropriate targets. Nano-topological features induced rapid cell growth is especially important towards the design of effective platforms to facilitate damaged neural circuit reconstruction. In this study, for the first time, feasibility of neuron-like PC12 cell growth on untreated and easy to prepare nanotextured surfaces has been carried out. The PC12 neuron-like cells were cultured on micro reactive ion etched  nanotextured glass coverslips. The effect of nanotextured topology as physical cue for the growth of PC12 cells was observed exclusively, eliminating the possible influence(s) of the enhanced concentration of coated materials on the surface. The cell density was observed to increase by almost 200% on nanotextured coverslips compared to plain coverslips. The morphology study indicated that PC12 cell attachment and growth on the nanotextured substrates did not launch any apoptotic machinery of the cell. Less than 5% cells deformed and depicted condensed nuclei with apoptotic bodies on nanotextured surfaces which is typical for the normal cell handling and culture. Enhanced PC12 cell proliferation by such novel and easy to prepare substrates is not only attractive for neurite outgrowth and guidance, but may be used to increase the affinity of similar cancerous cells (ex: B35 neuroblastoma) and rapid proliferation thereafter-towards the development of combinatorial theranostics to diagnose and treat aggressive cancers like neuroblastoma.

The influence of nanotexturing of poly(lactic-co-glycolic acid) films upon human ovarian cancer cell attachment

In this study, we have produced nanotextured poly(lactic-co-glycolic acid) (PLGA) films by using polystyrene (PS) particles as a template to make a polydimethylsiloxane mould against which PLGA is solvent cast. Biocompatible, biodegradable and nanotextured PLGA films were prepared with PS particles of diameter of 57, 99, 210, and 280 nm that produced domes of the same dimension in the PLGA surface. The effect of the particulate monolayer templating method was investigated to enable preparation of the films with uniformly ordered surface nanodomes. Cell attachment of a human ovarian cancer cell line (OVCAR3) alone and co-cultured with mesenchymal stem cells (MSCs) was evaluated on flat and topographically nano-patterned surfaces. Cell numbers were observed to increase on the nanotextured surfaces compared to non-textured surfaces both with OVCAR3 cultures and OVCAR3-MSC co-cultures at 24 and 48 h time points.

Effects of Nanotexture on Electrical Profiling of Single Tumor Cell and Detection of Cancer from Blood in Microfluidic Channels

Microfluidic channels have been implemented to detect cancer cells from blood using electrical measurement of each single cell from the sample. Every cell provided characteristic current profile based on its mechano-physical properties. Cancer cells not only showed higher translocation time and peak amplitude compared to blood cells, their pulse shape was also distinctively different. Prevalent microfluidic channels are plain but we created nanotexture on the channel walls using micro reactive ion etching (micro-RIE). The translocation behaviors of the metastatic renal cancer cells through plain and nanotextured PDMS microchannels showed clear differences. Nanotexture enhanced the cell-surface interactions and more than 50% tumor cells exhibited slower translocation through nanotextured channels compared to plain devices. On the other hand, most of the blood cells had very similar characteristics in both channels. Only 7.63% blood cells had slower translocation in nanotextured microchannels. The tumor cell detection efficiency from whole blood increased by 14% in nanotextured microchannels compared to plain channels. This interesting effect of nanotexture on translocation behavior of tumor cells is important for the early detection of cancer.