Bibliographystyle invalid, what am I doing wrong in my latex file or bibtex file?

One can't mix \bibliographystyle command and biblatex package. The style=... option is used for this feature.

Use \printbibliography and the preamble - only command \addbibresource for the 'cleaner' biblatex interface -- it's more up-to-date in conjunction with biber than bibtex alone.

\documentclass[11pt]{report}  
\usepackage{geometry}  
\usepackage{amsmath}  
\usepackage{acronym}  
\usepackage{times}  
\usepackage{epstopdf}  
\usepackage{amssymb}  
\usepackage{mathrsfs}  
\usepackage{latexsym}  
\usepackage{wrapfig}  
\usepackage[font={footnotesize,it}]{caption}  
\usepackage{url}  
\usepackage{float}    
\usepackage{titling}    
\renewcommand{\thechapter}{\Roman{chapter}}  
\renewcommand{\thesection}{\arabic{chapter}.\arabic{section}}  
\renewcommand{\thetable}{\arabic{chapter}.\arabic{table}}  
\renewcommand{\thefigure}{\arabic{chapter}.\arabic{figure}}  
\usepackage{hyperref}  
\usepackage{cleveref}  
\usepackage{graphics}  
\usepackage[pdftex]{graphicx}  
\usepackage{siunitx}  
\usepackage{booktabs}  
\usepackage{microtype}  
\usepackage{subfigure}  
\usepackage[english]{babel}\addto\captionsenglish  
{\renewcommand{\bibname}{References}}  
\usepackage[backend=bibtex,style=numeric]{biblatex}  %backend=biber is 'better'  
\usepackage{multirow}  
\usepackage{textcomp}  
\usepackage{csquotes} %Package biblatex Warning: 'babel/polyglossia' detected but 'csquotes' missing.  
\usepackage{listings}  
\usepackage{babel,blindtext}  
%\usepackage[T1]{fontenc}   
\geometry{a4paper} % ... or letter or a4paper or a5paper or ...  %\usepackage[parfill]{parskip}    % Activate to begin paragraphs with an empty line rather than an indent  
\DeclareGraphicsRule{.tif}{png}{.png}{`convert #1 `dirname #1`/`basename #1 .tif`.png}  
\hypersetup{colorlinks,
            citecolor=black,  
            filecolor=black,  
            linkcolor=black,  
            urlcolor=blue }  
\setlength{\textwidth}{420pt}  
\oddsidemargin = 0.5cm  
\def \m{$\mu$}   
\def \g{$\gamma$}  
\def \b{$\beta^-$}  
\def \a{$\alpha$}  
\newcommand{\unicode}[1]{{}}  

%\bibliography{Bronvermelding}  


\addbibresource{Bronvermelding.bib}  

\begin{document}  


Textfile bla bla bla  



\cite{radioactivedecay2}
\cite{DLS1}  

\printbibliography
\end{document}  

@online{introduction1,  
author = {IARC Globocan 2012},  
title = {Section of Cancer Surveillance},  
year = {2012},  
url = {http://globocan.iarc.fr/Pages/fact_sheets_cancer.aspx},  
}  

@article{introduction2,  
  title={Global burden of cancers attributable to infections in 2008: a review and   synthetic analysis},  
  author={De Martel, Catherine and Ferlay, Jacques and Franceschi, Silvia and Vignat,   J{\'e}r{\^o}me and Bray, Freddie and Forman, David and Plummer, Martyn},  
  journal={The lancet oncology},  
  volume={13},  
  number={6},    
  pages={607--615},  
  year={2012},  
  publisher={Elsevier}  
}  

@article{introduction3,  
  title={On the receiving end—patient perception of the side-effects of cancer   chemotherapy},  
  author={Coates, Alan and Abraham, Suzanne and Kaye, S Betai and Sowerbutts, Timothy and   Frewin, Cheryl and Fox, RM and Tattersall, MHN},  
  journal={European Journal of Cancer and Clinical Oncology},  
  volume={19},  
  number={2},  
  pages={203--208},  
  year={1983},  
  publisher={Elsevier}  
}  

@article{introduction4,  
author = {Discher, Dennis E. and Ahmed, Fariyal},  
title = {POLYMERSOMES},  
journal = {Annual Review of Biomedical Engineering},  
volume = {8},  
number = {1},  
pages = {323-341}, 
year = {2006},  
doi = {10.1146/annurev.bioeng.8.061505.095838},  
note ={PMID: 16834559},  
}

@article{theory1,  
author = {Discher, Dennis E. and Ahmed, Fariyal},  
title = {POLYMERSOMES},  
journal = {Annual Review of Biomedical Engineering},  
volume = {8},  
number = {1},  
pages = {323-341},  
year = {2006},  
doi = {10.1146/annurev.bioeng.8.061505.095838},  
    note ={PMID: 16834559},  
}  


@article{theory2,  
  title={Cross-linked polymersome membranes: vesicles with broadly adjustable   properties},  
  author={Discher, Bohdana M and Bermudez, Harry and Hammer, Daniel A and Discher, Dennis   E and Won, You-Yeon and Bates, Frank S},  
  journal={The Journal of Physical Chemistry B},  
  volume={106},  
  number={11},  
  pages={2848--2854},  
  year={2002},  
  publisher={ACS Publications}  
}  

@article{theory3,  
  title={Biocompatible and biodegradable polymersomes as delivery vehicles in biomedical   applications},  
  author={Liu, Gong-Yan and Chen, Chao-Jian and Ji, Jian},  
  journal={Soft Matter},  
  volume={8},  
  number={34},  
  pages={8811--8821},  
  year={2012},  
  publisher={Royal Society of Chemistry}  
}  

@article{theory4,  
  title={Polymersomes as radionuclide carriers loaded via active ion transport through   the hydrophobic bilayer},  
  author={Wang, G and De Kruijff, R and Stuart, MCA and Mendes, E and Wolterbeek, HT and   Denkova, AG},  
  journal={Soft Matter},  
  volume={9},  
  number={3},  
  pages={727--734},  
  year={2013},  
  publisher={Royal Society of Chemistry}  
}  

@article{theory5,  
  title={Emerging applications of polymersomes in delivery: from molecular dynamics to   shrinkage of tumors},  
  author={Discher, Dennis E and Ortiz, Vanessa and Srinivas, Goundla and Klein, Michael L   and Kim, Younghoon and Christian, David and Cai, Shenshen and Photos, Peter and Ahmed,   Fariyal},  
  journal={Progress in polymer science},  
  volume={32},  
  number={8},  
  pages={838--857},  
  year={2007},  
  publisher={Elsevier}  
}  

@article{theory6,  
  title={Self assembling polymers as polymersomes for drug delivery},  
  author={Prakash Jain, Jay and Yenet Ayen, Wubeante and Kumar, Neeraj},  
  journal={Current pharmaceutical design},  
  volume={17},  
  number={1},  
  pages={65--79},  
  year={2011},  
  publisher={Bentham Science Publishers}  
}

@article{theorybiodegradability1,  
    title={Suitability of Biodegradable Polymersomes as Radionuclide Carriers},  
    author={Sanders, T.J.},  
    year={2014},  
    publisher={et. al.}  
    }  

@article{Decayscheme1,  
  title={Table of Radionuclides (Comments on evaluation)},  
  author={Be, MM and Chist{\'e}, V and Dulieu, C and Browne, E and Baglin, C and Chechev,   V and Kuzmenco, N and Helmer, R and MACMAHON, D and LEE, KB},  
  journal={CEA, France},  
  year={1999}  
}  

@article{introduction5,  
    title={Role of Block Copolymer Nanoconstructs in Cancer Therapy},  
    author={K. K. Upadhyay and H. G. Agrawal and C. Upadhyay and C. Schatz and J. F. Le   Meins and Ambikanandan Misra and Sebastian Lecommandoux},  
    journal= {Critical Reviews™ in Therapeutic Drug Carrier Systems},  
    volume={26},  
    issn={0743-4863},  
    year={2009},  
    number={2},  
    pages={157--205}  
}  

@article{DLS1,  
title = "Emerging applications of polymersomes in delivery: From molecular dynamics to   shrinkage of tumors ",  
journal = "Progress in Polymer Science ",  
volume = "32",  
number = "8–9",  
pages = "838 - 857",  
year = "2007",  
note = "Polymers in Biomedical Applications ",  
issn = "0079-6700",  
author = "Dennis E. Discher and Vanessa Ortiz and Goundla Srinivas and Michael L. Klein   and Younghoon Kim and David Christian and Shenshen Cai and Peter Photos and Fariyal   Ahmed",  
keywords = "Liposomes",  
keywords = "Amphiphile",  
keywords = "Block copolymers",  
keywords = "Nano-particles",  
keywords = "Controlled release "  
}  

@book{radioactivedecay1,  
  title={Radioactivity And Radioactive Decay},  
  author={Jha, D.K.},  
  isbn={9788171418701},  
  publisher={Discovery Publishing House Pvt. Limited}  
}  

@book{radioactivedecay2,  
  title={Radioactivity: Introduction and History: Introduction and History},  
  author={L'Annunziata, Michael F},  
  year={2007},  
  publisher={Elsevier}  
}  

enter image description here


When I tried @Christian Hupfer's answer, I get a bunch of "undefined control sequence" errors. When I removed [backend=bibtex,style=numeric] I could get it to compile again, but then I was back to the original problem.

I fixed it by modifying that line to \usepackage[style=numeric,sorting=none]{biblatex}