Microplate-Based Cryopreservation of Adherent-Cultured Human Cell Lines Using Amino Acids and Proteins

With the progression of regenerative medicine and cell therapy, the importance of cryopreservation techniques for cultured cells continues to rise. Traditional cryoprotectants, such as dimethyl sulfoxide and glycerol, are effective in cryopreserving suspended cells, but they do not demonstrate sufficient efficacy for two-dimensional (2D)-cultured cells. In the past decade, small molecules and polymers have been studied as cryoprotectants. Some L-amino acids have been reported to be natural and biocompatible cryoprotectants. However, the cryoprotective effects of D-amino acids have not been investigated for such organized cells. In the present study, the cryoprotective effects of D- and L-amino acids and previously reported cryoprotectants were assessed using HepG2 cells cultured on a microplate without suspending the cells. d-Proline had the highest cryoprotective effect on 2D-cultured cells. The composition of the cell-freezing solution and freezing conditions were then optimized. The d-proline-containing cell-freezing solution also effectively worked for other cell lines. To minimize the amount of animal-derived components, fetal bovine serum in the cell freezing solution was substituted with bovine serum albumin and StemFit (a commercial supplement for stem cell induction). Further investigations on the mechanism of cryopreservation suggested that d-proline protected enzymes essential for cell survival from freeze-induced damage. In conclusion, an effective and xeno-free cell-freezing solution was produced using d-proline combined with dimethyl sulfoxide and StemFit for 2D-cultured cells.

SFAlab: image-based quantification of mechano-active ventral actin stress fibers in adherent cells

Ventral actin stress fibers (SFs) are a subset of actin SFs that begin and terminate at focal adhesion (FA) complexes. Ventral SFs can transmit forces from and to the extracellular matrix and serve as a prominent mechanosensing and mechanotransduction machinery for cells. Therefore, quantitative analysis of ventral SFs can lead to deeper understanding of the dynamic mechanical interplay between cells and their extracellular matrix (mechanoreciprocity). However, the dynamic nature and organization of ventral SFs challenge their quantification, and current quantification tools mainly focus on all SFs present in cells and cannot discriminate between subsets. Here we present an image analysis-based computational toolbox, called SFAlab, to quantify the number of ventral SFs and the number of ventral SFs per FA, and provide spatial information about the locations of the identified ventral SFs. SFAlab is built as an all-in-one toolbox that besides analyzing ventral SFs also enables the identification and quantification of (the shape descriptors of) nuclei, cells, and FAs. We validated SFAlab for the quantification of ventral SFs in human fetal cardiac fibroblasts and demonstrated that SFAlab analysis i) yields accurate ventral SF detection in the presence of image imperfections often found in typical fluorescence microscopy images, and ii) is robust against user subjectivity and potential experimental artifacts. To demonstrate the usefulness of SFAlab in mechanobiology research, we modulated actin polymerization and showed that inhibition of Rho kinase led to a significant decrease in ventral SF formation and the number of ventral SFs per FA, shedding light on the importance of the RhoA pathway specifically in ventral SF formation. We present SFAlab as a powerful open source, easy to use image-based analytical tool to increase our understanding of mechanoreciprocity in adherent cells.

Development of supercooling preservation method of adherent cultured human cells

Cryopreservation of mammalian cells is an important technology; however, freezing damage due to osmotic pressure differences and ice crystal formation is inevitable. In addition, cryopreserved cells cannot be used immediately after thawing in many cases. Therefore, in this study, we developed a method for supercooling and preserving adherent cells using a precision temperature-controlled CO2 incubator. The effects of the cooling rate from 37 to -4°C, the warming rate from -4 to 37°C and a preservation solution on cell viability after storage were examined. Human hepatocarcinoma-derived cell line HepG2 cells, preserved with HypoThermosol FRS at -4°C with a cooling rate of -0.028°C/min (24 h from 37°C to -4°C) and warming to 37°C at a rate of +1.0°C/min (40 min from -4 to 37°C), displayed high cell viability after 14 days of preservation. The superiority of supercooling preservation at -4°C was demonstrated by comparing the obtained results with that of refrigerated preservation at +4°C. Cells preserved for 14 days under optimal conditions showed no cell shape abnormalities and may be used for experiments immediately after thawing. The optimized supercooling preservation method determined in this study is suitable for the temporary preservation of adherent cultured cells.

High-density adherent culture of CHO cells using rolled scaffold bioreactor

Rapid expansion of biopharmaceutical market calls for more efficient and reliable platforms to culture mammalian cells on a large scale. Stirred-tank bioreactors have been widely used for large-scale cell culture. However, it requires months of trials and errors to optimize culture conditions for each cell line. In this article, we extend our earlier studies on rolled scaffold (RS) bioreactors for high-density adherent cell culture and report two new implementations of RSs with greatly enhanced mass-manufacturability, termed as Mesh-RS and Fiber-RS. CHO-K1 cells were successfully expanded in Mesh-RS and Fiber-RS bioreactors with an average growth rate of 1.09 ± 0.04 1/day and 0.95 ± 0.07 1/day, which were higher than those reported in similar studies. Fiber-RS bioreactor exhibited a very high cell density of 72.8 × 10⁶  cells/ml. Besides, a dialyzer was integrated into the RS bioreactor to remove cellular waste and to replenish nutrients without disturbing the cells. By collecting the dialyzed media separately, the dialysis efficiency was significantly improved. In conclusion, the developed RS bioreactor has a strong potential to provide a highly reliable and easily scalable platform for large-scale cell culture in the biopharmaceutical industry.

Macrophage Heterogeneity in the Intestinal Cells of Salmon: Hints From Transcriptomic and Imaging Data

The intestine has many types of cells that are present mostly in the epithelium and lamina propria. The importance of the intestinal cells for the mammalian mucosal immune system is well-established. However, there is no in-depth information about many of the intestinal cells in teleosts. In our previous study, we reported that adherent intestinal cells (AIC) predominantly express macrophage-related genes. To gather further evidence that AIC include macrophage-like cells, we compared their phagocytic activity and morphology with those of adherent head kidney cells (AKC), previously characterized as macrophage-like cells. We also compared equally abundant as well as differentially expressed mRNAs and miRNAs between AIC and AKC. AIC had lower phagocytic activity and were larger and more circular than macrophage-like AKC. RNA-Seq data revealed that there were 18309 mRNAs, with 59 miRNAs that were equally abundant between AIC and AKC. Integrative analysis of the mRNA and miRNA transcriptomes revealed macrophage heterogeneity in both AIC and AKC. In addition, analysis of AIC and AKC transcriptomes revealed functional characteristics of mucosal and systemic macrophages. Five pairs with significant negative correlations between miRNA and mRNAs were linked to macrophages and epithelial cells and their interaction could be pointing to macrophage activation and differentiation. The potential macrophage markers suggested in this study should be investigated under different immune conditions to understand the exact macrophage phenotypes.

Delivery of Foreign Materials into Adherent Cells by Gold Nanoparticle-Mediated Photoporation

Delivering extracellular materials into adherent cells presents several challenges. A homemade photoporation platform, mediated by gold nanoparticles (AuNPs), was constructed to find a suitable method for finding all adherent cells in this process with high delivery efficiency. The thermal dynamics of AuNPs could be monitored. Based on this system, 60 nm AuNPs were selected to be attached to cells for optimal photoporation. After irradiating the cells covered with AuNPs using a nanosecond pulse laser, fluorescein isothiocyanate-dextran in the medium were delivered into optoporated adherent HeLa (human cervical cell lines) cells. The delivery efficiency and cell viability of this process were evaluated using a fluorescence microscope and flow cytometry. The experimental results showed that targeting cells using antibodies, laser irradiation from the top of the cell culture well, and reducing the cell medium are important for improving the delivery efficiency. The optimal loading efficiency for adherent HeLa cells was 53.4%.

Dancing with the Cells: Acoustic Microflows Generated by Oscillating Cells

The interaction of a sound or ultrasound wave with an elastic object, such as a microbubble, can give rise to a steady-state microstreaming flow in its surrounding liquid. Many microfluidic strategies for cell and particle manipulation, and analyte mixing, are based on this type of flow. In addition, there are reports that acoustic streaming can be generated in biological systems, for instance, in a mammalian inner ear. Here, new observations are reported that individual cells are able to induce microstreaming flow, when they are excited by controlled acoustic waves in vitro. Single adherent cells are exposed to an acoustic field inside a microfluidic device. The cell-induced microstreaming is then investigated by monitoring flow tracers around the cell, while the structure and extracellular environment of the cell are altered using different chemicals. The observations suggest that the maximum streaming flow induced by an MDA-MB-231 breast cancer cell can reach velocities on the order of mm s^-1 , and this maximum velocity is primarily governed by the overall cell stiffness. Therefore, such cell-induced microstreaming measurements, including flow pattern and velocity magnitude, may be used as label-free proxies of cellular mechanical properties, such as stiffness.

In vitro activities of telithromycin against Staphylococcus aureus biofilms compared with azithromycin, clindamycin, vancomycin and daptomycin

Introduction. Staphylococcus aureus biofilms are difficult to treat and the effect of telithromycin treatment is still unclear.Aim. This study aimed to explore the effect of telithromycin against Staphylococcus aureus biofilms compared with azithromycin, clindamycin, vancomycin and daptomycin.Methodology. Eight methicillin-susceptible and eight methicillin-resistant S. aureus isolates (MSSA and MRSA, respectively) were used for this study. Biofilm biomasses were detected by crystal violet staining and the adherent cells in the established biofilms were quantified by determination of colony-forming units (c.f.u.). The RNA levels of biofilm formation-related genes were determined by RT-qPCR.Results. Telithromycin [8× minimum inhibitory concentration (MIC)] eradicated more established biofilms than azithromycin or clindamycin in the four MSSA isolates, and eliminated the established biofilms of six MRSA isolates more effectively than vancomycin or daptomycin. Telithromycin (8× MIC) killed more adherent cells in the established biofilms than azithromycin or clindamycin in the six MSSA isolates, and killed more adherent cells than vancomycin in all eight MRSA isolates. Daptomycin also showed an excellent effect on the adherent cells of MRSA isolates, with similarresults to telithromycin. The effect of a subinhibitory concentration of telithromycin (1/4× MIC) was significantly superior to that of azithromycin or clindamycin, inhibiting the biofilm formation of six MSSA isolates and seven MRSA isolates more effectively than vancomycin or daptomycin. The RNA levels of agrA, agrC, clfA, icaA and sigB decreased when treated with telithromycin (1/4× MIC).Conclusions. Telithromycin is more effective than azithromycin, clindamycin, vancomycin, or daptomycin against S. aureus biofilms.

Microfluidic Device for Screening for Target Cell-Specific Binding Molecules by Using Adherent Cells

This paper proposes a microfluidic device for screening molecules such as aptamers, antibodies, proteins, etc. for target cell-specific binding molecules. The discovery of cancer cell-specific binding molecules was the goal of this study. Its functions include filtering non-target cell-binding molecules, trapping molecules on the surface of target cells, washing away unbound molecules, and collecting target cell-specific binding molecules from target cells. These functions were effectively implemented by using our previously developed micro pillar arrays for cell homogeneous dispersion and pneumatic microvalves for tall microchannels. The device was also equipped with serially connected filter chambers in which non-target cells were cultured to reduce the molecules binding to non-target cells as much as possible. We evaluated the performance of the device using cancer cell lines (N87 cells as target cells and HeLa cells as non-target cells) and two fluorescent dye-labeled antibodies: Anti-human epidermal growth factor receptor 2 (anti-HER2) antibody that binds to target cells and anti-integrin antibody that binds to non-target cells. The results showed that the device could reduce anti-integrin antibodies to the detection limit of fluorescent measurement and collect anti-HER2 antibodies from the target cells.

Cell Harvesting Methods Affect Cellular Integrity of Adherent Cells During Apoptosis Detection

BACKGROUND/AIM

Annexin V and propidium iodide (PI) dual staining is commonly applied in bioscience as a method to detect apoptosis. However, excessive handling of adherent cells may interfere with the integrity of plasma membrane and hence impede the accuracy of this method. Here, we exploited PI uptake as an indicator of cell integrity and investigated how cell harvesting methods and solutions involved in common apoptosis detection techniques affected measurement results.

MATERIALS AND METHODS

Different cell harvesting techniques, staining with PI and flow cytometry were performed.

RESULTS

Non-fixed scrapped cells revealed significantly higher fractions of PI-positive staining compared to non-fixed trypsinized cells. In the case of harvesting cells by scrapping, samples stained in binding buffer (68.30±3.55%) showed consistently higher PI-positive staining than samples stained in PBS (36.37±5.90%) in a significant manner (p=0.015).

CONCLUSION

Enzymatic harvesting using 0.25% trypsin instead of mechanical harvesting by rubber scraper caused less damage of cell integrity. Furthermore, the binding buffer used in the apoptosis detection protocol aggravated the existing plasma membrane damage caused by the rubber scraper.

GMP Production and Scale-Up of Adherent Neural Stem Cells with a Quantum Cell Expansion System

Cell-based therapies hold great promise for a myriad of clinical applications. However, as these therapies move from phase I to phase II and III trials, there is a need to improve scale-up of adherent cells for the production of larger good manufacturing practice (GMP) cell banks. As we advanced our neural stem cell (NSC)-mediated gene therapy trials for glioma to include dose escalation and multiple treatment cycles, GMP production using cell factories (CellStacks) generated insufficient neural stem cell (NSC) yields. To increase yield, we developed an expansion method using the hollow fiber quantum cell expansion (QCE) system. Seeding of 5.2 × 10⁷ NSCs in a single unit yielded up to 3 × 10⁹ cells within 10 days. These QCE NSCs showed genetic and functional stability equivalent to those expanded by conventional flask-based methods. We then expanded the NSCs in 7 units simultaneously to generate a pooled GMP-grade NSC clinical lot of more than 1.5 × 10¹⁰ cells in only 9 days versus 8 × 10⁹ over 6 weeks in CellStacks. We also adenovirally transduced our NSCs within the QCE. We found the QCE system enabled rapid cell expansion and increased yield while maintaining cell properties and reducing process time, labor, and costs with improved efficiency and reproducibility.

Role of psl Genes in Antibiotic Tolerance of Adherent Pseudomonas aeruginosa

Bacteria attached to a surface are generally more tolerant to antibiotics than their planktonic counterparts, even without the formation of a biofilm. The mechanism of antibiotic tolerance in biofilm communities is multifactorial, and the genetic background underlying this antibiotic tolerance has not yet been fully elucidated. Using transposon mutagenesis, we isolated a mutant with reduced tolerance to biapenem (relative to that of the wild type) from adherent cells. Sequencing analysis revealed a mutation in the pslL gene, which is part of the polysaccharide biosynthesis operon. The Pseudomonas aeruginosa PAO1ΔpslBCD mutant demonstrated a 100-fold-lower survival rate during the exposure of planktonic and biofilm cells to biapenem; a similar phenotype was observed in a mouse infection model and in clinical strains. Transcriptional analysis of adherent cells revealed increased expression of both pslA and pelA, which are directly regulated by bis-(3',5')-cyclic dimeric GMP (c-di-GMP). Inactivation of wspF resulted in significantly increased tolerance to biapenem due to increased production of c-di-GMP. The loss of pslBCD in the ΔwspF mutant background abolished the biapenem-tolerant phenotype of the ΔwspF mutant, underscoring the importance of psl in biapenem tolerance. Overexpression of PA2133, which can catalyze the degradation of c-di-GMP, led to a significant reduction in biapenem tolerance in adherent cells, indicating that c-di-GMP is essential in mediating the tolerance effect. The effect of pslBCD on antibiotic tolerance was evident, with 50- and 200-fold-lower survival in the presence of ofloxacin and tobramycin, respectively. We speculate that the psl genes, which are activated by surface adherence through elevated intracellular c-di-GMP levels, confer tolerance to antimicrobials.

Modeling Living Cells Response to Surface Tension and Chemical Patterns

Mechanobiology is an important epigenetic factor. It influences cell functioning and bears on gene induction, protein synthesis, cell growth, and differentiation. In the presence of patterned chemical cues, living cells can take shapes that are far from that of a drop of fluid. These shapes are characterized by inward curvatures that are pinned at the points of location of the cues. The mechanochemical interactions that orchestrate cell behavior is simulated and controlled by modeling the cells as made by parcels of fluid. Cells become drops that are then endowed with the presence of additional forces, generated on the fly, that effectively make them active. With the proper choice of the forces, the phenomena that emerge from the dynamics match quantitatively the experiments. A combination of hydrophilic and lipophilic forces acting between the beads of fluid allows the active drop to respond to patterned cues and form squares, pentagons, hexagons, and flowers, just as living cells do.

Micro- and Nanoscale Technologies for Delivery into Adherent Cells

Several recent micro- and nanotechnologies have provided novel methods for biological studies of adherent cells because the small features of these new biotools provide unique capabilities for accessing cells without the need for suspension or lysis. These novel approaches have enabled gentle but effective delivery of molecules into specific adhered target cells, with unprecedented spatial resolution. We review here recent progress in the development of these technologies with an emphasis on in vitro delivery into adherent cells utilizing mechanical penetration or electroporation. We discuss the major advantages and limitations of these approaches and propose possible strategies for improvements. Finally, we discuss the impact of these technologies on biological research concerning cell-specific temporal studies, for example non-destructive sampling and analysis of intracellular molecules.

A Selective and Purification-Free Strategy for Labeling Adherent Cells with Inorganic Nanoparticles

Cellular labeling with inorganic nanoparticles such as magnetic iron oxide nanoparticles, quantum dots, and fluorescent silica nanoparticles is an important method for the noninvasive visualization of cells using various imaging modalities. Currently, this is mainly achieved through the incubation of cultured cells with the nanoparticles that eventually reach the intracellular compartment through specific or nonspecific internalization. This classic method is advantageous in terms of simplicity and convenience, but it suffers from issues such as difficulties in fully removing free nanoparticles (suspended in solution) and the lack of selectivity on cell types. This article reports an innovative strategy for the specific labeling of adherent cells without the concern of freely suspended nanoparticles. This method relies on a nanocomposite film that is prepared by homogeneously dispersing nanoparticles within a biodegradable polymeric film. When adherent cells are seeded on the film, they adhere, spread, and filtrate into the film through the micropores formed during the film fabrication. The pre-embedded nanoparticles are thus internalized by the cells during this infiltration process. As an example, fluorescent silica nanoparticles were homogeneously distributed within a polycaprolactone film by utilizing cryomilling and heat pressing. Upon incubation within physiological buffer, no silica nanoparticles were released from the nanocomposite film even after 20 d of incubation. However, when adherent cells (e.g., human mesenchymal stem cells) were grown on the film, they became fluorescent after 3 d, which suggests internalization of silica nanoparticles by cells. In comparison, the suspension cells (e.g., monocytes) in the medium remained nonfluorescent no matter whether there was the presence of adherent cells or not. This strategy eventually allowed the selective and concomitant labeling of mesenchymal stem cells during their harvest from bone marrow aspiration.

Advances in cell culture: anchorage dependence

Anchorage-dependent cells are of great interest for various biotechnological applications. (i) They represent a formidable production means of viruses for vaccination purposes at very large scales (in 1000-6000 l reactors) using microcarriers, and in the last decade many more novel viral vaccines have been developed using this production technology. (ii) With the advent of stem cells and their use/potential use in clinics for cell therapy and regenerative medicine purposes, the development of novel culture devices and technologies for adherent cells has accelerated greatly with a view to the large-scale expansion of these cells. Presently, the really scalable systems--microcarrier/microcarrier-clump cultures using stirred-tank reactors--for the expansion of stem cells are still in their infancy. Only laboratory scale reactors of maximally 2.5 l working volume have been evaluated because thorough knowledge and basic understanding of critical issues with respect to cell expansion while retaining pluripotency and differentiation potential, and the impact of the culture environment on stem cell fate, etc., are still lacking and require further studies. This article gives an overview on critical issues common to all cell culture systems for adherent cells as well as specifics for different types of stem cells in view of small- and large-scale cell expansion and production processes.

Automated method for the rapid and precise estimation of adherent cell culture characteristics from phase contrast microscopy images

The quantitative determination of key adherent cell culture characteristics such as confluency, morphology, and cell density is necessary for the evaluation of experimental outcomes and to provide a suitable basis for the establishment of robust cell culture protocols. Automated processing of images acquired using phase contrast microscopy (PCM), an imaging modality widely used for the visual inspection of adherent cell cultures, could enable the non-invasive determination of these characteristics. We present an image-processing approach that accurately detects cellular objects in PCM images through a combination of local contrast thresholding and post hoc correction of halo artifacts. The method was thoroughly validated using a variety of cell lines, microscope models and imaging conditions, demonstrating consistently high segmentation performance in all cases and very short processing times (<1 s per 1,208 × 960 pixels image). Based on the high segmentation performance, it was possible to precisely determine culture confluency, cell density, and the morphology of cellular objects, demonstrating the wide applicability of our algorithm for typical microscopy image processing pipelines. Furthermore, PCM image segmentation was used to facilitate the interpretation and analysis of fluorescence microscopy data, enabling the determination of temporal and spatial expression patterns of a fluorescent reporter. We created a software toolbox (PHANTAST) that bundles all the algorithms and provides an easy to use graphical user interface. Source-code for MATLAB and ImageJ is freely available under a permissive open-source license. Biotechnol. Bioeng. 2014;111: 504–517. © 2013 Wiley Periodicals, Inc.

Cell harvesting method influences results of apoptosis analysis by annexin V staining

BACKGROUND

Annexin V staining is a common tool in apoptosis analysis. However, in adherently growing cell lines, substantial experimental bias could be introduced by membrane damage during the harvesting process. We investigated the influence of three different harvesting methods on the cell membrane integrity of six malignant cell lines.

MATERIALS AND METHODS

Six malignant cell lines were detached enzymatically by standard trypsinization or mechanically by scraping or wash-down by water jet. Membrane damage was measured by annexin V staining.

RESULTS

Three out of six cell lines (Mel-Ho, SW480 and PaTu 8988t) were not susceptible to membrane damage long the mothods used here. In HT 29, PANC 1 and A-673 cell lines, a high percentage of cells were stained positively for annexin V after mechanical detachment. These cells would wrongly be declared apoptotic cells.

CONCLUSION

To avoid substantial experimental bias caused by membrane damage, we recommend pre-testing of different harvesting methods before performing apoptosis analysis.

Cell-biomaterial mechanical interaction in the framework of tissue engineering: insights, computational modeling and perspectives

Tissue engineering is an emerging field of research which combines the use of cell-seeded biomaterials both in vitro and/or in vivo with the aim of promoting new tissue formation or regeneration. In this context, how cells colonize and interact with the biomaterial is critical in order to get a functional tissue engineering product. Cell-biomaterial interaction is referred to here as the phenomenon involved in adherent cells attachment to the biomaterial surface, and their related cell functions such as growth, differentiation, migration or apoptosis. This process is inherently complex in nature involving many physico-chemical events which take place at different scales ranging from molecular to cell body (organelle) levels. Moreover, it has been demonstrated that the mechanical environment at the cell-biomaterial location may play an important role in the subsequent cell function, which remains to be elucidated. In this paper, the state-of-the-art research in the physics and mechanics of cell-biomaterial interaction is reviewed with an emphasis on focal adhesions. The paper is focused on the different models developed at different scales available to simulate certain features of cell-biomaterial interaction. A proper understanding of cell-biomaterial interaction, as well as the development of predictive models in this sense, may add some light in tissue engineering and regenerative medicine fields.

Stem cell heterogeneity of mononucleated cells from murine peripheral blood: molecular analysis

The main purpose of this paper was to determine the heterogeneity of primary isolated mononucleated cells that originated from the peripheral blood system by observing molecular markers. The isolated cells were cultured in complete medium for 4 to 7 days prior to the separation of different cell types, that is, adherent and suspension. Following a total culture time of 14 days, adherent cells activated the Cd105 gene while suspension cells activated the Sca-1 gene. Both progenitor markers, Cbfa-1 and Ostf-1, were inactivated in both suspension and adherent cells after 14-day culture compared to cells cultured 3 days in designated differentiation medium. In conclusion, molecular analyses showed that primary mononucleated cells are heterogeneous, consisting of hematopoietic stem cells (suspension) and mesenchymal stem cells (adherent) while both cells contained no progenitor cells.

Fabrication and biological evaluation of uniform extracellular matrix coatings on discontinuous photolithography generated micropallet arrays

The recent identification of rare cell populations within tissues that are associated with specific biological behaviors, for example, progenitor cells, has illuminated a limitation of current technologies to study such adherent cells directly from primary tissues. The micropallet array is a recently developed technology designed to address this limitation by virtue of its capacity to isolate and recover single adherent cells on individual micropallets. The capacity to apply this technology to primary tissues and cells with restricted growth characteristics, particularly adhesion requirements, is critically dependent on the capacity to generate functional extracellular matrix (ECM) coatings. The discontinuous nature of the micropallet array surface provides specific constraints on the processes for generating the desired ECM coatings that are necessary to achieve the full functional capacity of the micropallet array. We have developed strategies, reported herein, to generate functional coatings with various ECM protein components: fibronectin, EHS tumor basement membrane extract, collagen, and laminin-5; confirmed by evaluation for rapid cellular adherence of four dissimilar cell types: fibroblast, breast epithelial, pancreatic epithelial, and myeloma. These findings are important for the dissemination and expanded use of micropallet arrays and similar microtechnologies requiring the integrated use of ECM protein coatings to promote cellular adherence.