Sandra Cruz

Dr. Sandra Cruz

Instituto Pedro Nunes - Laboratory for Wear, Testing & Materials
orcid

Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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29 February 2012 in Nanoscale
Verified
Journal Article
Closed access
PDF file
Gil GonçalvesGil Gonçalves
Gil Gonçalves
Sandra CruzSandra Cruz
Sandra Cruz
Amilcar RamalhoAmilcar Ramalho
Amilcar Ramalho
JGJosé Grácio
José Grácio
Paula MarquesPaula Marques
Paula Marques
Graphene oxide (GO) and functionalized carbon nanotubes (f-CNTs) (each in the concentration range of 0.01–1.00 wt/wt%) were investigated as the reinforcing agent in a poly(methyl methacrylate) (PMMA)/hydroxyapatite (HA) bone cement. Mixed results were obtained for the changes in the mechanical properties determined (storage modulus, bending strength, and elastic modulus) for the reinforced cement relative to the unreinforced counterpart; that is, some property changes were increased while others were decreased. We postulate that this outcome is a consequence of the fact that each of the nanofillers hampered the polymerization process in the cement; specifically, the nanofiller acts as a scavenger of the radicals produced during polymerization reaction due to the delocalized π-bonds. Results obtained from the chemical structure and polymer chain size distribution determined, respectively, by nuclear magnetic resonance and size exclusion chromatography analysis, on the polymer extracted from the specimens support the postulated mechanism. Furthermore, in the case of the 0.5 wt/wt% GO-reinforced cement, we showed that when the concentration of the radical species in the PMMA bone cement was doubled, mechanical properties markedly improved (relative to the value in the unreinforced cement), suggesting suppression of the aforementioned scavenger activity.

23 October 2012 in Nanotechnology
Verified
Journal Article
Closed access
MVM Vila
M Vila
MPM T Portolés
M T Portolés
Paula MarquesPaula Marques
Paula Marques
MFM J Feito
M J Feito
MMM C Matesanz
M C Matesanz
MVM Vallet-Regi
M Vallet-Regi
Graphene and more specifically, nanographene oxide (GO) has been proposed as a highly efficient antitumoral therapy agent. Nevertheless, its cell uptake kinetics, its influence in different types of cells and the possibility of controlling cellular internalization timing, is still a field that remains unexplored. Herein, different cell types have been cultured in vitro for several incubation periods in the presence of 0.075 mg ml(-1) pegylated GO solutions. GO uptake kinetics revealed differences in the agent's uptake amount and speed as a function of the type of cell involved. Osteoblast-like cells GO uptake is higher and faster without resulting in greater cell membrane damage. Moreover, the dependence on the commonly used PEG nature (number of branches) also influences the viability and cell uptake speed. These facts play an important role in the future definition of timing parameters and selective cell uptake control in order to achieve an effective therapy.

21 January 2016 in Sensors
Verified
Journal Article
Open access
PDF file
Sandra CruzSandra Cruz
Sandra Cruz
AGAndré F. Girão
André F. Girão
Gil GonçalvesGil Gonçalves
Gil Gonçalves
Paula MarquesPaula Marques
Paula Marques
This paper reviews recent advances in graphene-based biosensors development in order to obtain smaller and more portable devices with better performance for earlier cancer detection. In fact, the potential of Graphene for sensitive detection and chemical/biological free-label applications results from its exceptional physicochemical properties such as high electrical and thermal conductivity, aspect-ratio, optical transparency and remarkable mechanical and chemical stability. Herein we start by providing a general overview of the types of graphene and its derivatives, briefly describing the synthesis procedure and main properties. It follows the reference to different routes to engineer the graphene surface for sensing applications with organic biomolecules and nanoparticles for the development of advanced biosensing platforms able to detect/quantify the characteristic cancer biomolecules in biological fluids or overexpressed on cancerous cells surface with elevated sensitivity, selectivity and stability. We then describe the application of graphene in optical imaging methods such as photoluminescence and Raman imaging, electrochemical sensors for enzymatic biosensing, DNA sensing, and immunosensing. The bioquantification of cancer biomarkers and cells is finally discussed, particularly electrochemical methods such as voltammetry and amperometry which are generally adopted transducing techniques for the development of graphene based sensors for biosensing due to their simplicity, high sensitivity and low-cost. To close, we discuss the major challenges that graphene based biosensors must overcome in order to reach the necessary standards for the early detection of cancer biomarkers by providing reliable information about the patient disease stage.

1 February 2015 in Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
Verified
Journal Article
Closed access
YMY. Sheena Mary
Y. Sheena Mary
CPC. Yohannan Panicker
C. Yohannan Panicker
CKC.N. Kavitha
C.N. Kavitha
HYH.S. Yathirajan
H.S. Yathirajan
MSM.S. Siddegowda
M.S. Siddegowda
JWJaveed Ahmad War
Javeed Ahmad War

1 July 2008 in Journal of Colloid and Interface Science
Verified
Journal Article
Closed access
Artur ValenteArtur Valente
Artur Valente
HBHugh Burrows
Hugh Burrows
Sandra CruzSandra Cruz
Sandra Cruz
Rui PereiraRui Pereira
Rui Pereira
Ana RibeiroAna Ribeiro
Ana Ribeiro
VLVictor M.M. Lobo
Victor M.M. Lobo

1 February 2014 in Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy
Verified
Journal Article
Closed access
YMY. Shyma Mary
Y. Shyma Mary
PJP.J. Jojo
P.J. Jojo
CAChristian Van Alsenoy
Christian Van Alsenoy
MKManpreet Kaur
Manpreet Kaur
MSM.S. Siddegowda
M.S. Siddegowda
Sandra CruzSandra Cruz
Sandra Cruz