Bruce Chase

Biofunctionalization of electrospun PCL-based scaffolds with perlecan domain IV peptide to create a 3-D pharmacokinetic cancer model

Because prostate cancer cells metastasize to bone and exhibit osteoblastic features (osteomimicry), the interrelationships between bone-specific microenvironment and prostate cancer cells at sites of bone metastasis are critical to disease progression. In this work the bone marrow microenvironment in vitro was recreated both by tailoring scaffolds physical properties and by functionalizing electrospun polymer fibers with a bioactive peptide derived from domain IV of perlecan heparan sulfate proteoglycan. Electrospun poly (epsilon-caprolactone) (PCL) fibers and PCL/gelatin composite scaffolds were modified covalently with perlecan domain IV (PlnDIV) peptide. The expression of tight junction protein (E-cadherin) and focal adhesion kinase (FAK) phosphorylation on tyrosine 397 also were investigated. The described bioactive motif significantly enhanced adherence and infiltration of the metastatic prostate cancer cells on all modified electrospun substrates by day 5 post-seeding. Cells cultured on PlnDIV-modified matrices organized stress fibers and increased proliferation at statistically significant rates. Additional findings suggest that presence of PlnDIV peptide in the matrix reduced expression of tight junction protein and binding to PlnDIV peptide was accompanied by increased focal adhesion kinase (FAK) phosphorylation on tyrosine 397. We conclude that PlnDIV peptide supports key signaling events leading to proliferation, survival, and migration of C4-2B cancer cells; hence its incorporation into electrospun matrix is a key improvement to create a successful three-dimensional (3-D) pharmacokinetic cancer model.

Microfabricated Electrospun Collagen Membranes for 3-D Cancer Models and Drug Screening Applications

Invasive epithelial tumors form from cells that are released from their natural basement membrane and form 3-D structures that interact with each other and with the microenvironment of the stromal tissues around the tumor, which often contains collagen. Cancer cells, growing as monolayers on tissue culture plastic, do not reflect many of the properties of whole tumors. This shortcoming limits their ability to serve as models for testing of pharmacologically active compounds, including those that are being tested as antineoplastics. This work seeks to create new 3-D cellular materials possessing properties similar to those in native tissues surrounding cancers, specifically electrospun micro- and nanofibrous collagen scaffolds that support tumor growth in 3-D. We hypothesize that a 3-D culture system will provide a better replica of tumor growth in a native environment and, thus, better report the bioactivity of antineoplastic agents. In addition, we optimized conditions and identified physical characteristics that support growth of the highly invasive, prostate cancer bone metastatic cell line C4-2B on these matrices for use in anticancer drug studies. The effects of matrix porosity, fiber diameter, elasticity, and surface roughness on growth of cancer cells were evaluated. Data indicates that while cells attach and grow well on both nano- and microfibrous electrospun membranes, the microfibrous membrane represented a better approximation of the tumor microenvironment. It was also observed that C4-2B nonadherent cells migrated through the depth of two electrospun membranes and formed colonies resembling tumors on day 3. An apoptosis study revealed that cells on electrospun substrates were more resistant to both antineoplastic agents, docetaxel (DOC), and camptothecin (CAM) compared to the cells grown on standard collagen-coated tissue culture polystyrene (TCP). Growth, survival, and apoptosis were measured, as well as the differences in the apoptotic capabilities, of the two above-mentioned compounds compared to known clinical performance. We conclude that 3-D electrospun membranes are amenable to high throughput screening for cancer cell susceptibility and combination killing (Banerjee, S.; Hussain, M.; Wang, Z.; Saliganan, A.; Che, M.; Bonfil, D.; Cher, M.; Sarkar, F.H. Cancer Research, 2007, 67 (8), 3818-26).

The Use of a Near-Infrared Array Detector for Raman Spectroscopy beyond One Micron:

The performance characteristics of a multielement Ge array detector have been measured. The effects of read noise and dark signal on signal integration have been evaluated. The performance of this array for Raman spectroscopy with excitation at one micron has been compared with FT-Raman spectroscopy. It is an excellent detector for narrow-spectral-bandwidth Raman studies, and the sensitivity compares favorably with that for FT-Raman techniques.

Development of a Planar Array Infrared Reflection Spectrograph for Reflection–Absorption Spectroscopy of Thin Films at Metal and Water Surfaces

Planar array infrared (PA-IR) spectroscopy offers several advantages over Fourier transform infrared (FT-IR) methods, including ultrafast speed (< 100 μs temporal resolution) and excellent sensitivity. However, obtaining spectra in the range of 1800 to 1000 cm−1 of films at the air–water interface remains difficult due to the poor IR reflectivity of water, the extremely low concentration of the thin film on the water subphase, and the interference of water bands. In this study, we report a new planar array infrared reflection spectrograph (PA-IRRS), which has several advantages over conventional approaches. This instrument can record sample and reference spectra simultaneously with an instrumental setup that is the same as that of a single-beam instrument by splitting the incident infrared beam into two sections on a plane mirror (H) or a water trough. With this design, the instrument can accommodate large infrared accessories, such as a water trough, without a loss of infrared beam intensity. Water bands can be subtracted to obtain a high-quality spectrum for poly(L-lactic acid) Langmuir film on the water subphase with a resolution of about 6 cm−1 in 10.8 s. Hence, this PA-IRRS system has great potential for investigating the time-resolved dynamics of a broad range of Langmuir films, such as cellular membranes or biopolymers, on the water subphase.

Molecular rearrangement of metal-chelating lipid monolayers upon protein adsorption.

The controlled adsorption of proteins to well-defined monolayers is critical to advances in sensor and nanotechnology applications where selective adsorption of targeted species is of interest. In the studies reported here, we developed vibrational spectroscopic methods to gain molecular insight into the effect of single-site versus multiple-site binding of proteins to metal-chelating monolayers at an air-water interface. Analysis of real-time planar array infrared reflection-absorption spectra revealed that a Cu(II)-chelated DSIDA lipid monolayer (Cu(2+)-DSIDA) was readily disrupted by adsorption of myoglobin as demonstrated by a blue shift of 1.7 cm(-1) in the v(as)(CH(2)) stretching mode and a reduced peak intensity over a period of 5 h. However, a Zn(II)-chelated monolayer was not affected by the adsorption of either protein, suggesting that multisite binding of protein on the Cu(2+)-DSIDA results in monolayer disruption. Further studies demonstrated that in film form, adsorption of myoglobin to the Cu(2+)-DSIDA perturbed the secondary structures of myoglobin, especially the alpha-helical, random structure, and extended structures. However, no distinct change was observed during adsorption of lysozyme. These results demonstrate the utility of these methods for monitoring the molecular rearrangement of both metal-charged lipid monolayers and proteins that occur during adsorption of a protein with a strong affinity for the monolayer.

Artifact Correction in Temperature-Dependent Attenuated Total Reflection Infrared (ATR-IR) Spectra:

A spectral processing method was developed and tested for analyzing temperature-dependent attenuated total reflection infrared (ATR-IR) spectra of aliphatic polyesters. Spectra of a bio-based, biodegradable polymer, 3.9 mol% 3HHx poly[(R)-3-hydroxybutyrate-co-(R)-3-hydroxyhexanoate] (PHBHx), were analyzed and corrected prior to analysis using two-dimensional correlation spectroscopy (2D-COS). Removal of the temperature variation of diamond absorbance, correction of the baseline, ATR correction, and appropriate normalization were key to generating more reliable data. Both the processing steps and order were important. A comparison to differential scanning calorimetry (DSC) analysis indicated that the normalization method should be chosen with caution to avoid unintentional trends and distortions of the crystalline sensitive bands.

A Selection of Ground-Breaking Papers Published in Applied Spectroscopy

In mid-1945, as World War II neared its end, a group of scientists in and around New York City formed a new organization, called The Society for Applied Spectroscopy. They also began a publication, The Society for Applied Spectroscopy Bulletin. There were some technical articles in it, and they were tutorial in nature. Over the next few years the Bulletin became a scientific journal, renamed Applied Spectroscopy. When a national spectroscopic society was formed in 1958, the New York group donated its name and the publication to the national organization and became the New York Section. The cover of the January 1996 issue marked the 50th anniversary of Applied Spectroscopy. The upper left inset shows the cover of an early issue of the Bulletin. The cover of the journal in 1959 is shown on the top right. The national society assumed publication of the journal in 1960. The middle image shows the cover three years later, unchanged but for a new logo. The other images are photos of six of the seven Editors-in-Chief during the first fifty years. Two of them, John Ferraro and Leopold May, also served terms as President of SAS. In celebration of the 50th anniversary of the Society for Applied Spectroscopy, a group of past and present journal editors were asked to compile a selection of past papers published in Applied Spectroscopy, representing ground-breaking research and covering the wide range of topics that have appeared in the journal over the years. The editors compiled a collection from the Meggers Award winning papers and from the list of the most highly cited papers that have appeared in Applied Spectroscopy. The William F. Meggers Award (previously called the Journal Award) has been given annually since 1960 to the authors of the most outstanding paper published in that year. It is remarkable how many important innovations in spectroscopy have been honored by this award. A complete list of the Meggers Award/Journal Award papers appears elsewhere in this issue. The impact of top papers in a field is often reflected in citations to that work in subsequent publications. The number of citations to the articles in the collection below was reported by Science Citation Index. The articles are arranged in chronological order.